2D Arrays - Java Programming

You're building a seating chart for a theater. Each seat has a row and column. A 2D array lets you store and access data by two coordinates - perfect for grids, game boards, and spreadsheets.

Create a seating chart

Initialize a 2D array to represent a grid of seats.

                            example
                            rows = 3, cols = 4 (default)rows = 5cols = 6
                        

                            CreateGrid.java
                        
Replay: real traced execution (multi-file project)

                            public class CreateGrid {
    public static void main(String[] args) {
        // Theater seating chart: rows x seats per row
        int rows = 3;
        int cols = 4;

        // Create 2D array for seat numbers
        int[][] seating = new int[rows][cols];

        // Assign seat numbers (1, 2, 3, ...)
        int seatNumber = 1;
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                seating[row][col] = seatNumber;
                seatNumber++;
            }
        }

        // Display the seating chart
        System.out.println("=== Theater Seating Chart ===");
        for (int row = 0; row < rows; row++) {
            System.out.print("Row " + (row + 1) + ": ");
            for (int col = 0; col < cols; col++) {
                System.out.print(seating[row][col] + "\t");
            }
            System.out.println();
        }

        int totalSeats = rows * cols;
        System.out.println("Total seats: " + totalSeats);
    }
}
public class CreateGrid {
    public static void main(String[] args) {
        // Theater seating chart: rows x seats per row
        int rows = 5;
        int cols = 4;

        // Create 2D array for seat numbers
        int[][] seating = new int[rows][cols];

        // Assign seat numbers (1, 2, 3, ...)
        int seatNumber = 1;
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                seating[row][col] = seatNumber;
                seatNumber++;
            }
        }

        // Display the seating chart
        System.out.println("=== Theater Seating Chart ===");
        for (int row = 0; row < rows; row++) {
            System.out.print("Row " + (row + 1) + ": ");
            for (int col = 0; col < cols; col++) {
                System.out.print(seating[row][col] + "\t");
            }
            System.out.println();
        }

        int totalSeats = rows * cols;
        System.out.println("Total seats: " + totalSeats);
    }
}
public class CreateGrid {
    public static void main(String[] args) {
        // Theater seating chart: rows x seats per row
        int rows = 3;
        int cols = 6;

        // Create 2D array for seat numbers
        int[][] seating = new int[rows][cols];

        // Assign seat numbers (1, 2, 3, ...)
        int seatNumber = 1;
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                seating[row][col] = seatNumber;
                seatNumber++;
            }
        }

        // Display the seating chart
        System.out.println("=== Theater Seating Chart ===");
        for (int row = 0; row < rows; row++) {
            System.out.print("Row " + (row + 1) + ": ");
            for (int col = 0; col < cols; col++) {
                System.out.print(seating[row][col] + "\t");
            }
            System.out.println();
        }

        int totalSeats = rows * cols;
        System.out.println("Total seats: " + totalSeats);
    }
}

                        
1rows ← 3, cols ← 4, seatNumber ← 1⋯2public class CreateGrid {3    public static void main(String[] args) {4        // Theater seating chart: rows x seats per row5        int rows→ 3 = 3;    //@var=_,56        int cols→ 4 = 4;    //@var=_,67        8        // Create 2D array for seat numbers9        int[][] seating = new int[rows][cols];  //?seats10        11        // Assign seat numbers (1, 2, 3, ...)12        int seatNumber→ 1 = 1;13        for (int row = 0; row < rows; row++) {⋯
2for (int row = 0; row < rows; row++)pass 1 of 3⋯12int seatNumber = 1;13for (int row0 = 0; row < rows3; row++) {14    for (int col = 0; col < cols; col++) {⋯All 3 passes — pass 1 is the card abovepassrow
10
21
32
3seating[row][col] ← 1, seatNumber ← 2pass 1 of 12⋯13for (int row = 0; row < rows; row++) {14    for (int col0 = 0; col < cols4; col++) {15        seating[row][col]→ 1 = seatNumber1;16        seatNumber→ 2++;17    }⋯All 12 passes — pass 1 is the card abovepasscolrowseating[row][col]seatNumber
1000 → 11 → 2
2100 → 22 → 3
3200 → 33 → 4
4300 → 44 → 5
5010 → 55 → 6
6110 → 66 → 7
7210 → 77 → 8
8310 → 88 → 9
9020 → 99 → 10
10120 → 1010 → 11
11220 → 1111 → 12
12320 → 1212 → 13
4System.out.println("=== Theater Seating Chart ===");⋯20// Display the seating chart21System.out.println("=== Theater Seating Chart ===");22for (int row = 0; row < rows; row++) {⋯output=== Theater Seating Chart ===
5for (int row = 0; row < rows; row++)pass 1 of 3⋯21System.out.println("=== Theater Seating Chart ===");22for (int row0 = 0; row < rows3; row++) {23    System.out.print("Row " + (row0 + 1) + ": ");24    for (int col = 0; col < cols; col++) {⋯outputRow 1: All 3 passes — pass 1 is the card abovepassrow
10
21
32
6for (int col = 0; col < cols; col++)pass 1 of 12⋯23System.out.print("Row " + (row + 1) + ": ");24for (int col0 = 0; col < cols4; col++) {25    System.out.print(seating[row][col]1 + "\t");26}⋯output1	All 12 passes — pass 1 is the card abovepasscolseating[row][col]row
1010
2120
3230
4340
5051
6161
7271
8381
9092
101102
112112
123122
7System.out.println();⋯26    }27    System.out.println();28}⋯
8System.out.println();⋯26    }27    System.out.println();28}⋯
9System.out.println();⋯26    }27    System.out.println();28}⋯
10totalSeats ← 12⋯30    int totalSeats→ 12 = rows3 * cols4;31    System.out.println("Total seats: " + totalSeats12);32}⋯outputTotal seats: 12
1rows ← 5, cols ← 4, seatNumber ← 11public class CreateGrid {2    public static void main(String[] args) {3        // Theater seating chart: rows x seats per row4        int rows→ 5 = 5;5        int cols→ 4 = 4;6        7        // Create 2D array for seat numbers8        int[][] seating = new int[rows][cols];9        10        // Assign seat numbers (1, 2, 3, ...)11        int seatNumber→ 1 = 1;12        for (int row = 0; row < rows; row++) {⋯
2for (int row = 0; row < rows; row++)pass 1 of 5⋯11int seatNumber = 1;12for (int row0 = 0; row < rows5; row++) {13    for (int col = 0; col < cols; col++) {⋯All 5 passes — pass 1 is the card abovepassrow
10
21
32
43
54
3seating[row][col] ← 1, seatNumber ← 2pass 1 of 20⋯12for (int row = 0; row < rows; row++) {13    for (int col0 = 0; col < cols4; col++) {14        seating[row][col]→ 1 = seatNumber1;15        seatNumber→ 2++;16    }⋯20 passes — pass 1 is the card abovepasscolrowseating[row][col]seatNumber
1000 → 11 → 2
2100 → 22 → 3
3200 → 33 → 4
4300 → 44 → 5
5010 → 55 → 6
6110 → 66 → 7
7210 → 77 → 8
8310 → 88 → 9
9020 → 99 → 10
⋯ 9 more passes ⋯
19240 → 1919 → 20
20340 → 2020 → 21
4System.out.println("=== Theater Seating Chart ===");⋯19// Display the seating chart20System.out.println("=== Theater Seating Chart ===");21for (int row = 0; row < rows; row++) {⋯output=== Theater Seating Chart ===
5for (int row = 0; row < rows; row++)pass 1 of 5⋯20System.out.println("=== Theater Seating Chart ===");21for (int row0 = 0; row < rows5; row++) {22    System.out.print("Row " + (row0 + 1) + ": ");23    for (int col = 0; col < cols; col++) {⋯outputRow 1: All 5 passes — pass 1 is the card abovepassrow
10
21
32
43
54
6for (int col = 0; col < cols; col++)pass 1 of 20⋯22System.out.print("Row " + (row + 1) + ": ");23for (int col0 = 0; col < cols4; col++) {24    System.out.print(seating[row][col]1 + "\t");25}⋯output1	20 passes — pass 1 is the card abovepasscolseating[row][col]row
1010
2120
3230
4340
5051
6161
7271
8381
9092
⋯ 9 more passes ⋯
192194
203204
7System.out.println();⋯25    }26    System.out.println();27}⋯
8System.out.println();⋯25    }26    System.out.println();27}⋯
9System.out.println();⋯25    }26    System.out.println();27}⋯
10System.out.println();⋯25    }26    System.out.println();27}⋯
11System.out.println();⋯25    }26    System.out.println();27}⋯
12totalSeats ← 20⋯29    int totalSeats→ 20 = rows5 * cols4;30    System.out.println("Total seats: " + totalSeats20);31}⋯outputTotal seats: 20
1rows ← 3, cols ← 6, seatNumber ← 11public class CreateGrid {2    public static void main(String[] args) {3        // Theater seating chart: rows x seats per row4        int rows→ 3 = 3;5        int cols→ 6 = 6;6        7        // Create 2D array for seat numbers8        int[][] seating = new int[rows][cols];9        10        // Assign seat numbers (1, 2, 3, ...)11        int seatNumber→ 1 = 1;12        for (int row = 0; row < rows; row++) {⋯
2for (int row = 0; row < rows; row++)pass 1 of 3⋯11int seatNumber = 1;12for (int row0 = 0; row < rows3; row++) {13    for (int col = 0; col < cols; col++) {⋯All 3 passes — pass 1 is the card abovepassrow
10
21
32
3seating[row][col] ← 1, seatNumber ← 2pass 1 of 18⋯12for (int row = 0; row < rows; row++) {13    for (int col0 = 0; col < cols6; col++) {14        seating[row][col]→ 1 = seatNumber1;15        seatNumber→ 2++;16    }⋯18 passes — pass 1 is the card abovepasscolrowseating[row][col]seatNumber
1000 → 11 → 2
2100 → 22 → 3
3200 → 33 → 4
4300 → 44 → 5
5400 → 55 → 6
6500 → 66 → 7
7010 → 77 → 8
8110 → 88 → 9
9210 → 99 → 10
⋯ 7 more passes ⋯
17420 → 1717 → 18
18520 → 1818 → 19
4System.out.println("=== Theater Seating Chart ===");⋯19// Display the seating chart20System.out.println("=== Theater Seating Chart ===");21for (int row = 0; row < rows; row++) {⋯output=== Theater Seating Chart ===
5for (int row = 0; row < rows; row++)pass 1 of 3⋯20System.out.println("=== Theater Seating Chart ===");21for (int row0 = 0; row < rows3; row++) {22    System.out.print("Row " + (row0 + 1) + ": ");23    for (int col = 0; col < cols; col++) {⋯outputRow 1: All 3 passes — pass 1 is the card abovepassrow
10
21
32
6for (int col = 0; col < cols; col++)pass 1 of 18⋯22System.out.print("Row " + (row + 1) + ": ");23for (int col0 = 0; col < cols6; col++) {24    System.out.print(seating[row][col]1 + "\t");25}⋯output1	18 passes — pass 1 is the card abovepasscolseating[row][col]row
1010
2120
3230
4340
5450
6560
7071
8181
9291
⋯ 7 more passes ⋯
174172
185182
7System.out.println();⋯25    }26    System.out.println();27}⋯
8System.out.println();⋯25    }26    System.out.println();27}⋯
9System.out.println();⋯25    }26    System.out.println();27}⋯
10totalSeats ← 18⋯29    int totalSeats→ 18 = rows3 * cols6;30    System.out.println("Total seats: " + totalSeats18);31}⋯outputTotal seats: 18

All 3 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2

All 12 passes — pass 1 is the card above
pass	`col`	`row`	`seating[row][col]`	`seatNumber`
1	0	0	0 → 1	1 → 2
2	1	0	0 → 2	2 → 3
3	2	0	0 → 3	3 → 4
4	3	0	0 → 4	4 → 5
5	0	1	0 → 5	5 → 6
6	1	1	0 → 6	6 → 7
7	2	1	0 → 7	7 → 8
8	3	1	0 → 8	8 → 9
9	0	2	0 → 9	9 → 10
10	1	2	0 → 10	10 → 11
11	2	2	0 → 11	11 → 12
12	3	2	0 → 12	12 → 13

All 3 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2

All 12 passes — pass 1 is the card above
pass	`col`	`seating[row][col]`	`row`
1	0	1	0
2	1	2	0
3	2	3	0
4	3	4	0
5	0	5	1
6	1	6	1
7	2	7	1
8	3	8	1
9	0	9	2
10	1	10	2
11	2	11	2
12	3	12	2

All 5 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2
4	3
5	4

20 passes — pass 1 is the card above
pass	`col`	`row`	`seating[row][col]`	`seatNumber`
1	0	0	0 → 1	1 → 2
2	1	0	0 → 2	2 → 3
3	2	0	0 → 3	3 → 4
4	3	0	0 → 4	4 → 5
5	0	1	0 → 5	5 → 6
6	1	1	0 → 6	6 → 7
7	2	1	0 → 7	7 → 8
8	3	1	0 → 8	8 → 9
9	0	2	0 → 9	9 → 10
⋯ 9 more passes ⋯
19	2	4	0 → 19	19 → 20
20	3	4	0 → 20	20 → 21

All 5 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2
4	3
5	4

20 passes — pass 1 is the card above
pass	`col`	`seating[row][col]`	`row`
1	0	1	0
2	1	2	0
3	2	3	0
4	3	4	0
5	0	5	1
6	1	6	1
7	2	7	1
8	3	8	1
9	0	9	2
⋯ 9 more passes ⋯
19	2	19	4
20	3	20	4

All 3 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2

18 passes — pass 1 is the card above
pass	`col`	`row`	`seating[row][col]`	`seatNumber`
1	0	0	0 → 1	1 → 2
2	1	0	0 → 2	2 → 3
3	2	0	0 → 3	3 → 4
4	3	0	0 → 4	4 → 5
5	4	0	0 → 5	5 → 6
6	5	0	0 → 6	6 → 7
7	0	1	0 → 7	7 → 8
8	1	1	0 → 8	8 → 9
9	2	1	0 → 9	9 → 10
⋯ 7 more passes ⋯
17	4	2	0 → 17	17 → 18
18	5	2	0 → 18	18 → 19

All 3 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2

18 passes — pass 1 is the card above
pass	`col`	`seating[row][col]`	`row`
1	0	1	0
2	1	2	0
3	2	3	0
4	3	4	0
5	4	5	0
6	5	6	0
7	0	7	1
8	1	8	1
9	2	9	1
⋯ 7 more passes ⋯
17	4	17	2
18	5	18	2

A 2D array is an "array of arrays". Declare with int[][] grid = new int[rows][cols].

2D array Array of arrays: `int[][] grid`. Access with `grid[row][col]`.

Access a specific seat

Look up a value using row and column indices.

                            example
                            wantRow = 1, wantCol = 4 (default)wantRow = 0wantCol = 0
                        

                            AccessElement.java
                        
Replay: real traced execution (multi-file project)

                            public class AccessElement {
    public static void main(String[] args) {
        // Ticket prices by section (rows) and day (columns)
        // Rows: 0=Front, 1=Middle, 2=Back
        // Cols: 0=Mon, 1=Tue, 2=Wed, 3=Thu, 4=Fri
        int[][] prices = {
            {50, 50, 55, 55, 75},   // Front row
            {40, 40, 45, 45, 60},   // Middle row
            {25, 25, 30, 30, 45}    // Back row
        };

        // Customer wants: middle section, Friday
        int wantRow = 1;
        int wantCol = 4;

        int price = prices[wantRow][wantCol];

        String[] sections = {"Front", "Middle", "Back"};
        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};

        System.out.println("=== Ticket Lookup ===");
        System.out.println("Section: " + sections[wantRow]);
        System.out.println("Day: " + days[wantCol]);
        System.out.println("Price: $" + price);

        // Show full price chart
        System.out.println("\n=== Full Price Chart ===");
        System.out.print("        ");
        for (String day : days) {
            System.out.print(day.substring(0, 3) + "\t");
        }
        System.out.println();

        for (int r = 0; r < prices.length; r++) {
            System.out.print(sections[r] + "\t");
            for (int c = 0; c < prices[r].length; c++) {
                System.out.print("$" + prices[r][c] + "\t");
            }
            System.out.println();
        }
    }
}
public class AccessElement {
    public static void main(String[] args) {
        // Ticket prices by section (rows) and day (columns)
        // Rows: 0=Front, 1=Middle, 2=Back
        // Cols: 0=Mon, 1=Tue, 2=Wed, 3=Thu, 4=Fri
        int[][] prices = {
            {50, 50, 55, 55, 75},   // Front row
            {40, 40, 45, 45, 60},   // Middle row
            {25, 25, 30, 30, 45}    // Back row
        };

        // Customer wants: middle section, Friday
        int wantRow = 0;
        int wantCol = 4;

        int price = prices[wantRow][wantCol];

        String[] sections = {"Front", "Middle", "Back"};
        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};

        System.out.println("=== Ticket Lookup ===");
        System.out.println("Section: " + sections[wantRow]);
        System.out.println("Day: " + days[wantCol]);
        System.out.println("Price: $" + price);

        // Show full price chart
        System.out.println("\n=== Full Price Chart ===");
        System.out.print("        ");
        for (String day : days) {
            System.out.print(day.substring(0, 3) + "\t");
        }
        System.out.println();

        for (int r = 0; r < prices.length; r++) {
            System.out.print(sections[r] + "\t");
            for (int c = 0; c < prices[r].length; c++) {
                System.out.print("$" + prices[r][c] + "\t");
            }
            System.out.println();
        }
    }
}
public class AccessElement {
    public static void main(String[] args) {
        // Ticket prices by section (rows) and day (columns)
        // Rows: 0=Front, 1=Middle, 2=Back
        // Cols: 0=Mon, 1=Tue, 2=Wed, 3=Thu, 4=Fri
        int[][] prices = {
            {50, 50, 55, 55, 75},   // Front row
            {40, 40, 45, 45, 60},   // Middle row
            {25, 25, 30, 30, 45}    // Back row
        };

        // Customer wants: middle section, Friday
        int wantRow = 1;
        int wantCol = 0;

        int price = prices[wantRow][wantCol];

        String[] sections = {"Front", "Middle", "Back"};
        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};

        System.out.println("=== Ticket Lookup ===");
        System.out.println("Section: " + sections[wantRow]);
        System.out.println("Day: " + days[wantCol]);
        System.out.println("Price: $" + price);

        // Show full price chart
        System.out.println("\n=== Full Price Chart ===");
        System.out.print("        ");
        for (String day : days) {
            System.out.print(day.substring(0, 3) + "\t");
        }
        System.out.println();

        for (int r = 0; r < prices.length; r++) {
            System.out.print(sections[r] + "\t");
            for (int c = 0; c < prices[r].length; c++) {
                System.out.print("$" + prices[r][c] + "\t");
            }
            System.out.println();
        }
    }
}

                        
1wantRow ← 1, wantCol ← 4, price ← 60⋯2public class AccessElement {3    public static void main(String[] args) {4        // Ticket prices by section (rows) and day (columns)5        // Rows: 0=Front, 1=Middle, 2=Back6        // Cols: 0=Mon, 1=Tue, 2=Wed, 3=Thu, 4=Fri7        int[][] prices = {8            {50, 50, 55, 55, 75},   // Front row9            {40, 40, 45, 45, 60},   // Middle row  10            {25, 25, 30, 30, 45}    // Back row11        };12        13        // Customer wants: middle section, Friday14        int wantRow→ 1 = 1;  //?rowcol   //@var=_,015        int wantCol→ 4 = 4;              //@var=_,016        17        int price→ 60 = prices[wantRow][wantCol]60;18        19        String[] sections = {"Front", "Middle", "Back"};20        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};21        22        System.out.println("=== Ticket Lookup ===");23        System.out.println("Section: " + sections[wantRow]Middle);24        System.out.println("Day: " + days[wantCol]Friday);25        System.out.println("Price: $" + price60);26        27        // Show full price chart28        System.out.println("\n=== Full Price Chart ===");29        System.out.print("        ");30        for (String day : days) {⋯output=== Ticket Lookup ===
Section: Middle
Day: Friday
Price: $60

=== Full Price Chart ===
        
2for (String day : days)pass 1 of 5⋯29System.out.print("        ");30for (String dayMonday : days) {31    System.out.print(day.substring(0, 3) + "\t");32}⋯outputMon	All 5 passes — pass 1 is the card abovepassday
1Monday
2Tuesday
3Wednesday
4Thursday
5Friday
3System.out.println();⋯32}33System.out.println();⋯
4for (int r = 0; r < prices.length; r++)pass 1 of 3⋯35for (int r0 = 0; r < prices.length3; r++) {36    System.out.print(sections[r]Front + "\t");37    for (int c = 0; c < prices[r].length; c++) {⋯outputFront	All 3 passes — pass 1 is the card abovepassrsections[r]
10Front
21Middle
32Back
5for (int c = 0; c < prices[r].length; c++)pass 1 of 15⋯36System.out.print(sections[r] + "\t");37for (int c0 = 0; c < prices[r].length5; c++) {38    System.out.print("$" + prices[r][c]50 + "\t");39}⋯output$50	15 passes — pass 1 is the card abovepasscrprices[r][c]
10050
21050
32055
43055
54075
60140
71140
82145
93145
⋯ 4 more passes ⋯
143230
154245
6System.out.println();⋯39    }40    System.out.println();41}⋯
7System.out.println();⋯39    }40    System.out.println();41}⋯
8System.out.println();⋯39    }40    System.out.println();41}⋯
1wantRow ← 0, wantCol ← 4, price ← 751public class AccessElement {2    public static void main(String[] args) {3        // Ticket prices by section (rows) and day (columns)4        // Rows: 0=Front, 1=Middle, 2=Back5        // Cols: 0=Mon, 1=Tue, 2=Wed, 3=Thu, 4=Fri6        int[][] prices = {7            {50, 50, 55, 55, 75},   // Front row8            {40, 40, 45, 45, 60},   // Middle row  9            {25, 25, 30, 30, 45}    // Back row10        };11        12        // Customer wants: middle section, Friday13        int wantRow→ 0 = 0;14        int wantCol→ 4 = 4;15        16        int price→ 75 = prices[wantRow][wantCol]75;17        18        String[] sections = {"Front", "Middle", "Back"};19        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};20        21        System.out.println("=== Ticket Lookup ===");22        System.out.println("Section: " + sections[wantRow]Front);23        System.out.println("Day: " + days[wantCol]Friday);24        System.out.println("Price: $" + price75);25        26        // Show full price chart27        System.out.println("\n=== Full Price Chart ===");28        System.out.print("        ");29        for (String day : days) {⋯output=== Ticket Lookup ===
Section: Front
Day: Friday
Price: $75

=== Full Price Chart ===
        
2for (String day : days)pass 1 of 5⋯28System.out.print("        ");29for (String dayMonday : days) {30    System.out.print(day.substring(0, 3) + "\t");31}⋯outputMon	All 5 passes — pass 1 is the card abovepassday
1Monday
2Tuesday
3Wednesday
4Thursday
5Friday
3System.out.println();⋯31}32System.out.println();⋯
4for (int r = 0; r < prices.length; r++)pass 1 of 3⋯34for (int r0 = 0; r < prices.length3; r++) {35    System.out.print(sections[r]Front + "\t");36    for (int c = 0; c < prices[r].length; c++) {⋯outputFront	All 3 passes — pass 1 is the card abovepassrsections[r]
10Front
21Middle
32Back
5for (int c = 0; c < prices[r].length; c++)pass 1 of 15⋯35System.out.print(sections[r] + "\t");36for (int c0 = 0; c < prices[r].length5; c++) {37    System.out.print("$" + prices[r][c]50 + "\t");38}⋯output$50	15 passes — pass 1 is the card abovepasscrprices[r][c]
10050
21050
32055
43055
54075
60140
71140
82145
93145
⋯ 4 more passes ⋯
143230
154245
6System.out.println();⋯38    }39    System.out.println();40}⋯
7System.out.println();⋯38    }39    System.out.println();40}⋯
8System.out.println();⋯38    }39    System.out.println();40}⋯
1wantRow ← 1, wantCol ← 0, price ← 401public class AccessElement {2    public static void main(String[] args) {3        // Ticket prices by section (rows) and day (columns)4        // Rows: 0=Front, 1=Middle, 2=Back5        // Cols: 0=Mon, 1=Tue, 2=Wed, 3=Thu, 4=Fri6        int[][] prices = {7            {50, 50, 55, 55, 75},   // Front row8            {40, 40, 45, 45, 60},   // Middle row  9            {25, 25, 30, 30, 45}    // Back row10        };11        12        // Customer wants: middle section, Friday13        int wantRow→ 1 = 1;14        int wantCol→ 0 = 0;15        16        int price→ 40 = prices[wantRow][wantCol]40;17        18        String[] sections = {"Front", "Middle", "Back"};19        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};20        21        System.out.println("=== Ticket Lookup ===");22        System.out.println("Section: " + sections[wantRow]Middle);23        System.out.println("Day: " + days[wantCol]Monday);24        System.out.println("Price: $" + price40);25        26        // Show full price chart27        System.out.println("\n=== Full Price Chart ===");28        System.out.print("        ");29        for (String day : days) {⋯output=== Ticket Lookup ===
Section: Middle
Day: Monday
Price: $40

=== Full Price Chart ===
        
2for (String day : days)pass 1 of 5⋯28System.out.print("        ");29for (String dayMonday : days) {30    System.out.print(day.substring(0, 3) + "\t");31}⋯outputMon	All 5 passes — pass 1 is the card abovepassday
1Monday
2Tuesday
3Wednesday
4Thursday
5Friday
3System.out.println();⋯31}32System.out.println();⋯
4for (int r = 0; r < prices.length; r++)pass 1 of 3⋯34for (int r0 = 0; r < prices.length3; r++) {35    System.out.print(sections[r]Front + "\t");36    for (int c = 0; c < prices[r].length; c++) {⋯outputFront	All 3 passes — pass 1 is the card abovepassrsections[r]
10Front
21Middle
32Back
5for (int c = 0; c < prices[r].length; c++)pass 1 of 15⋯35System.out.print(sections[r] + "\t");36for (int c0 = 0; c < prices[r].length5; c++) {37    System.out.print("$" + prices[r][c]50 + "\t");38}⋯output$50	15 passes — pass 1 is the card abovepasscrprices[r][c]
10050
21050
32055
43055
54075
60140
71140
82145
93145
⋯ 4 more passes ⋯
143230
154245
6System.out.println();⋯38    }39    System.out.println();40}⋯
7System.out.println();⋯38    }39    System.out.println();40}⋯
8System.out.println();⋯38    }39    System.out.println();40}⋯

All 5 passes — pass 1 is the card above
pass	`day`
1	Monday
2	Tuesday
3	Wednesday
4	Thursday
5	Friday

All 3 passes — pass 1 is the card above
pass	`r`	`sections[r]`
1	0	Front
2	1	Middle
3	2	Back

15 passes — pass 1 is the card above
pass	`c`	`r`	`prices[r][c]`
1	0	0	50
2	1	0	50
3	2	0	55
4	3	0	55
5	4	0	75
6	0	1	40
7	1	1	40
8	2	1	45
9	3	1	45
⋯ 4 more passes ⋯
14	3	2	30
15	4	2	45

All 5 passes — pass 1 is the card above
pass	`day`
1	Monday
2	Tuesday
3	Wednesday
4	Thursday
5	Friday

All 3 passes — pass 1 is the card above
pass	`r`	`sections[r]`
1	0	Front
2	1	Middle
3	2	Back

15 passes — pass 1 is the card above
pass	`c`	`r`	`prices[r][c]`
1	0	0	50
2	1	0	50
3	2	0	55
4	3	0	55
5	4	0	75
6	0	1	40
7	1	1	40
8	2	1	45
9	3	1	45
⋯ 4 more passes ⋯
14	3	2	30
15	4	2	45

All 5 passes — pass 1 is the card above
pass	`day`
1	Monday
2	Tuesday
3	Wednesday
4	Thursday
5	Friday

All 3 passes — pass 1 is the card above
pass	`r`	`sections[r]`
1	0	Front
2	1	Middle
3	2	Back

15 passes — pass 1 is the card above
pass	`c`	`r`	`prices[r][c]`
1	0	0	50
2	1	0	50
3	2	0	55
4	3	0	55
5	4	0	75
6	0	1	40
7	1	1	40
8	2	1	45
9	3	1	45
⋯ 4 more passes ⋯
14	3	2	30
15	4	2	45

Access with two indices: grid[1][2] means row 1, column 2.

Mark a seat as reserved

Update a value at a specific position.

                            example
                            reserveRow = 1, reserveCol = 2 (default)reserveRow = 0reserveCol = 1
                        

                            UpdateCell.java
                        
Replay: real traced execution (multi-file project)

                            public class UpdateCell {
    public static void main(String[] args) {
        // Seating chart: 0 = available, 1 = reserved
        int[][] seats = {
            {0, 0, 0, 0},
            {0, 0, 0, 0},
            {0, 0, 0, 0}
        };

        // Customer reservations (row, col)
        int reserveRow = 1;
        int reserveCol = 2;

        System.out.println("=== Before Reservation ===");
        printSeating(seats);

        // Make the reservation
        seats[reserveRow][reserveCol] = 1;

        System.out.println("\n=== After Reserving Row " +
            (reserveRow + 1) + ", Seat " + (reserveCol + 1) + " ===");
        printSeating(seats);

        // Reserve more seats
        seats[0][0] = 1;
        seats[2][3] = 1;

        System.out.println("\n=== After Additional Reservations ===");
        printSeating(seats);

        // Count available seats
        int available = 0;
        for (int[] row : seats) {
            for (int seat : row) {
                if (seat == 0) available++;
            }
        }
        System.out.println("\nAvailable seats: " + available);
    }

    static void printSeating(int[][] seats) {
        System.out.println("  1 2 3 4");
        for (int r = 0; r < seats.length; r++) {
            System.out.print((r + 1) + " ");
            for (int c = 0; c < seats[r].length; c++) {
                System.out.print(seats[r][c] == 0 ? "O " : "X ");
            }
            System.out.println();
        }
    }
}
public class UpdateCell {
    public static void main(String[] args) {
        // Seating chart: 0 = available, 1 = reserved
        int[][] seats = {
            {0, 0, 0, 0},
            {0, 0, 0, 0},
            {0, 0, 0, 0}
        };

        // Customer reservations (row, col)
        int reserveRow = 0;
        int reserveCol = 2;

        System.out.println("=== Before Reservation ===");
        printSeating(seats);

        // Make the reservation
        seats[reserveRow][reserveCol] = 1;

        System.out.println("\n=== After Reserving Row " +
            (reserveRow + 1) + ", Seat " + (reserveCol + 1) + " ===");
        printSeating(seats);

        // Reserve more seats
        seats[0][0] = 1;
        seats[2][3] = 1;

        System.out.println("\n=== After Additional Reservations ===");
        printSeating(seats);

        // Count available seats
        int available = 0;
        for (int[] row : seats) {
            for (int seat : row) {
                if (seat == 0) available++;
            }
        }
        System.out.println("\nAvailable seats: " + available);
    }

    static void printSeating(int[][] seats) {
        System.out.println("  1 2 3 4");
        for (int r = 0; r < seats.length; r++) {
            System.out.print((r + 1) + " ");
            for (int c = 0; c < seats[r].length; c++) {
                System.out.print(seats[r][c] == 0 ? "O " : "X ");
            }
            System.out.println();
        }
    }
}
public class UpdateCell {
    public static void main(String[] args) {
        // Seating chart: 0 = available, 1 = reserved
        int[][] seats = {
            {0, 0, 0, 0},
            {0, 0, 0, 0},
            {0, 0, 0, 0}
        };

        // Customer reservations (row, col)
        int reserveRow = 1;
        int reserveCol = 1;

        System.out.println("=== Before Reservation ===");
        printSeating(seats);

        // Make the reservation
        seats[reserveRow][reserveCol] = 1;

        System.out.println("\n=== After Reserving Row " +
            (reserveRow + 1) + ", Seat " + (reserveCol + 1) + " ===");
        printSeating(seats);

        // Reserve more seats
        seats[0][0] = 1;
        seats[2][3] = 1;

        System.out.println("\n=== After Additional Reservations ===");
        printSeating(seats);

        // Count available seats
        int available = 0;
        for (int[] row : seats) {
            for (int seat : row) {
                if (seat == 0) available++;
            }
        }
        System.out.println("\nAvailable seats: " + available);
    }

    static void printSeating(int[][] seats) {
        System.out.println("  1 2 3 4");
        for (int r = 0; r < seats.length; r++) {
            System.out.print((r + 1) + " ");
            for (int c = 0; c < seats[r].length; c++) {
                System.out.print(seats[r][c] == 0 ? "O " : "X ");
            }
            System.out.println();
        }
    }
}

                        
1reserveRow ← 1, reserveCol ← 2⋯2public class UpdateCell {3    public static void main(String[] args) {4        // Seating chart: 0 = available, 1 = reserved5        int[][] seats = {6            {0, 0, 0, 0},7            {0, 0, 0, 0},8            {0, 0, 0, 0}9        };10        11        // Customer reservations (row, col)12        int reserveRow→ 1 = 1;    //@var=_,013        int reserveCol→ 2 = 2;    //@var=_,114        15        System.out.println("=== Before Reservation ===");16        printSeating(seats);⋯output=== Before Reservation ===
2static void printSeating(int[][] seats)pass 1 of 3⋯42static void printSeating(int[][] seats) {43    System.out.println("  1 2 3 4");44    for (int r = 0; r < seats.length; r++) {⋯output  1 2 3 4
3for (int r = 0; r < seats.length; r++)pass 1 of 9⋯43System.out.println("  1 2 3 4");44for (int r0 = 0; r < seats.length3; r++) {45    System.out.print((r0 + 1) + " ");46    for (int c = 0; c < seats[r].length; c++) {⋯output1 All 9 passes — pass 1 is the card abovepassr
10
21
32
40
51
62
70
81
92
4for (int c = 0; c < seats[r].length; c++)pass 1 of 36⋯45System.out.print((r + 1) + " ");46for (int c0 = 0; c < seats[r].length4; c++) {47    System.out.print(seats[r][c]0 == 0 ? "O " : "X ");48}⋯outputO 36 passes — pass 1 is the card abovepasscrseats[r][c]
1000
2100
3200
4300
5010
6110
7210
8310
9020
⋯ 25 more passes ⋯
35220
36321
5System.out.println();⋯48    }49    System.out.println();50}⋯
6System.out.println();⋯48    }49    System.out.println();50}⋯
7seats[reserveRow][reserveCol] ← 1⋯15    System.out.println("=== Before Reservation ===");16    printSeating(seats);17    18    // Make the reservation19    seats[reserveRow][reserveCol]→ 1 = 1;  //?update20    21    System.out.println("\n=== After Reserving Row " + 22        (reserveRow1 + 1) + ", Seat " + (reserveCol2 + 1) + " ===");23    printSeating(seats);24    25    // Reserve more seats26    seats[0][0] = 1;  //@var=_,!27    seats[2][3] = 1;  //@var=_,!28    29    System.out.println("\n=== After Additional Reservations ===");  //@var=_,!30    printSeating(seats);  //@var=_,!31    32    // Count available seats33    int available = 0;34    for (int[] row : seats) {35        for (int seat : row) {36            if (seat == 0) available++;37        }38    }39    System.out.println("\nAvailable seats: " + available);40}4142static void printSeating(int[][] seats) {43    System.out.println("  1 2 3 4");44    for (int r = 0; r < seats.length; r++) {45        System.out.print((r + 1) + " ");46        for (int c = 0; c < seats[r].length; c++) {47            System.out.print(seats[r][c] == 0 ? "O " : "X ");48        }49        System.out.println();50    }⋯output
=== After Reserving Row 2, Seat 3 ===
8System.out.println();⋯48    }49    System.out.println();50}⋯
9System.out.println();⋯48    }49    System.out.println();50}⋯
10seats[0][0] ← 1, seats[2][3] ← 1⋯22        (reserveRow + 1) + ", Seat " + (reserveCol + 1) + " ===");23    printSeating(seats);24    25    // Reserve more seats26    seats[0][0]→ 1 = 1;  //@var=_,!27    seats[2][3]→ 1 = 1;  //@var=_,!28    29    System.out.println("\n=== After Additional Reservations ===");  //@var=_,!30    printSeating(seats);  //@var=_,!31    32    // Count available seats33    int available = 0;34    for (int[] row : seats) {35        for (int seat : row) {36            if (seat == 0) available++;37        }38    }39    System.out.println("\nAvailable seats: " + available);40}4142static void printSeating(int[][] seats) {43    System.out.println("  1 2 3 4");44    for (int r = 0; r < seats.length; r++) {45        System.out.print((r + 1) + " ");46        for (int c = 0; c < seats[r].length; c++) {47            System.out.print(seats[r][c] == 0 ? "O " : "X ");48        }49        System.out.println();50    }⋯output
=== After Additional Reservations ===
11System.out.println();⋯48    }49    System.out.println();50}⋯
12System.out.println();⋯48    }49    System.out.println();50}⋯
13available ← 0⋯29    System.out.println("\n=== After Additional Reservations ===");  //@var=_,!30    printSeating(seats);  //@var=_,!31    32    // Count available seats33    int available→ 0 = 0;34    for (int[] row : seats) {35        for (int seat : row) {36            if (seat == 0) available++;37        }38    }39    System.out.println("\nAvailable seats: " + available);40}4142static void printSeating(int[][] seats) {43    System.out.println("  1 2 3 4");44    for (int r = 0; r < seats.length; r++) {45        System.out.print((r + 1) + " ");46        for (int c = 0; c < seats[r].length; c++) {47            System.out.print(seats[r][c] == 0 ? "O " : "X ");48        }49        System.out.println();50    }⋯
14for (int[] row : seats)pass 1 of 3⋯33int available = 0;34for (int[] row : seats) {35    for (int seat : row) {⋯
15for (int seat : row)pass 1 of 12⋯34for (int[] row : seats) {35    for (int seat1 : row) {36        if (seat == 0) available++;⋯All 12 passes — pass 1 is the card abovepassseat
11
20
30
40
50
60
71
80
90
100
110
121
16available ← 1pass 1 of 9⋯35for (int seat : row) {36    if (seat0 == 0) available→ 1++;37}⋯All 9 passes — pass 1 is the card abovepassavailable
10 → 1
21 → 2
32 → 3
43 → 4
54 → 5
65 → 6
76 → 7
87 → 8
98 → 9
17System.out.println(" Available seats: " + available);⋯38    }39    System.out.println("\nAvailable seats: " + available9);40}⋯output
Available seats: 9
1reserveRow ← 0, reserveCol ← 21public class UpdateCell {2    public static void main(String[] args) {3        // Seating chart: 0 = available, 1 = reserved4        int[][] seats = {5            {0, 0, 0, 0},6            {0, 0, 0, 0},7            {0, 0, 0, 0}8        };9        10        // Customer reservations (row, col)11        int reserveRow→ 0 = 0;12        int reserveCol→ 2 = 2;13        14        System.out.println("=== Before Reservation ===");15        printSeating(seats);⋯output=== Before Reservation ===
2static void printSeating(int[][] seats)pass 1 of 3⋯41static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {⋯output  1 2 3 4
3for (int r = 0; r < seats.length; r++)pass 1 of 9⋯42System.out.println("  1 2 3 4");43for (int r0 = 0; r < seats.length3; r++) {44    System.out.print((r0 + 1) + " ");45    for (int c = 0; c < seats[r].length; c++) {⋯output1 All 9 passes — pass 1 is the card abovepassr
10
21
32
40
51
62
70
81
92
4for (int c = 0; c < seats[r].length; c++)pass 1 of 36⋯44System.out.print((r + 1) + " ");45for (int c0 = 0; c < seats[r].length4; c++) {46    System.out.print(seats[r][c]0 == 0 ? "O " : "X ");47}⋯outputO 36 passes — pass 1 is the card abovepasscrseats[r][c]
1000
2100
3200
4300
5010
6110
7210
8310
9020
⋯ 25 more passes ⋯
35220
36321
5System.out.println();⋯47    }48    System.out.println();49}⋯
6System.out.println();⋯47    }48    System.out.println();49}⋯
7seats[reserveRow][reserveCol] ← 1⋯14    System.out.println("=== Before Reservation ===");15    printSeating(seats);16    17    // Make the reservation18    seats[reserveRow][reserveCol]→ 1 = 1;19    20    System.out.println("\n=== After Reserving Row " + 21        (reserveRow0 + 1) + ", Seat " + (reserveCol2 + 1) + " ===");22    printSeating(seats);23    24    // Reserve more seats25    seats[0][0] = 1;26    seats[2][3] = 1;27    28    System.out.println("\n=== After Additional Reservations ===");29    printSeating(seats);30    31    // Count available seats32    int available = 0;33    for (int[] row : seats) {34        for (int seat : row) {35            if (seat == 0) available++;36        }37    }38    System.out.println("\nAvailable seats: " + available);39}4041static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {44        System.out.print((r + 1) + " ");45        for (int c = 0; c < seats[r].length; c++) {46            System.out.print(seats[r][c] == 0 ? "O " : "X ");47        }48        System.out.println();49    }⋯output
=== After Reserving Row 1, Seat 3 ===
8System.out.println();⋯47    }48    System.out.println();49}⋯
9System.out.println();⋯47    }48    System.out.println();49}⋯
10seats[0][0] ← 1, seats[2][3] ← 1⋯21        (reserveRow + 1) + ", Seat " + (reserveCol + 1) + " ===");22    printSeating(seats);23    24    // Reserve more seats25    seats[0][0]→ 1 = 1;26    seats[2][3]→ 1 = 1;27    28    System.out.println("\n=== After Additional Reservations ===");29    printSeating(seats);30    31    // Count available seats32    int available = 0;33    for (int[] row : seats) {34        for (int seat : row) {35            if (seat == 0) available++;36        }37    }38    System.out.println("\nAvailable seats: " + available);39}4041static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {44        System.out.print((r + 1) + " ");45        for (int c = 0; c < seats[r].length; c++) {46            System.out.print(seats[r][c] == 0 ? "O " : "X ");47        }48        System.out.println();49    }⋯output
=== After Additional Reservations ===
11System.out.println();⋯47    }48    System.out.println();49}⋯
12System.out.println();⋯47    }48    System.out.println();49}⋯
13available ← 0⋯28    System.out.println("\n=== After Additional Reservations ===");29    printSeating(seats);30    31    // Count available seats32    int available→ 0 = 0;33    for (int[] row : seats) {34        for (int seat : row) {35            if (seat == 0) available++;36        }37    }38    System.out.println("\nAvailable seats: " + available);39}4041static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {44        System.out.print((r + 1) + " ");45        for (int c = 0; c < seats[r].length; c++) {46            System.out.print(seats[r][c] == 0 ? "O " : "X ");47        }48        System.out.println();49    }⋯
14for (int[] row : seats)pass 1 of 3⋯32int available = 0;33for (int[] row : seats) {34    for (int seat : row) {⋯
15for (int seat : row)pass 1 of 12⋯33for (int[] row : seats) {34    for (int seat1 : row) {35        if (seat == 0) available++;⋯All 12 passes — pass 1 is the card abovepassseat
11
20
31
40
50
60
70
80
90
100
110
121
16available ← 1pass 1 of 9⋯34for (int seat : row) {35    if (seat0 == 0) available→ 1++;36}⋯All 9 passes — pass 1 is the card abovepassavailable
10 → 1
21 → 2
32 → 3
43 → 4
54 → 5
65 → 6
76 → 7
87 → 8
98 → 9
17System.out.println(" Available seats: " + available);⋯37    }38    System.out.println("\nAvailable seats: " + available9);39}⋯output
Available seats: 9
1reserveRow ← 1, reserveCol ← 11public class UpdateCell {2    public static void main(String[] args) {3        // Seating chart: 0 = available, 1 = reserved4        int[][] seats = {5            {0, 0, 0, 0},6            {0, 0, 0, 0},7            {0, 0, 0, 0}8        };9        10        // Customer reservations (row, col)11        int reserveRow→ 1 = 1;12        int reserveCol→ 1 = 1;13        14        System.out.println("=== Before Reservation ===");15        printSeating(seats);⋯output=== Before Reservation ===
2static void printSeating(int[][] seats)pass 1 of 3⋯41static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {⋯output  1 2 3 4
3for (int r = 0; r < seats.length; r++)pass 1 of 9⋯42System.out.println("  1 2 3 4");43for (int r0 = 0; r < seats.length3; r++) {44    System.out.print((r0 + 1) + " ");45    for (int c = 0; c < seats[r].length; c++) {⋯output1 All 9 passes — pass 1 is the card abovepassr
10
21
32
40
51
62
70
81
92
4for (int c = 0; c < seats[r].length; c++)pass 1 of 36⋯44System.out.print((r + 1) + " ");45for (int c0 = 0; c < seats[r].length4; c++) {46    System.out.print(seats[r][c]0 == 0 ? "O " : "X ");47}⋯outputO 36 passes — pass 1 is the card abovepasscrseats[r][c]
1000
2100
3200
4300
5010
6110
7210
8310
9020
⋯ 25 more passes ⋯
35220
36321
5System.out.println();⋯47    }48    System.out.println();49}⋯
6System.out.println();⋯47    }48    System.out.println();49}⋯
7seats[reserveRow][reserveCol] ← 1⋯14    System.out.println("=== Before Reservation ===");15    printSeating(seats);16    17    // Make the reservation18    seats[reserveRow][reserveCol]→ 1 = 1;19    20    System.out.println("\n=== After Reserving Row " + 21        (reserveRow1 + 1) + ", Seat " + (reserveCol1 + 1) + " ===");22    printSeating(seats);23    24    // Reserve more seats25    seats[0][0] = 1;26    seats[2][3] = 1;27    28    System.out.println("\n=== After Additional Reservations ===");29    printSeating(seats);30    31    // Count available seats32    int available = 0;33    for (int[] row : seats) {34        for (int seat : row) {35            if (seat == 0) available++;36        }37    }38    System.out.println("\nAvailable seats: " + available);39}4041static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {44        System.out.print((r + 1) + " ");45        for (int c = 0; c < seats[r].length; c++) {46            System.out.print(seats[r][c] == 0 ? "O " : "X ");47        }48        System.out.println();49    }⋯output
=== After Reserving Row 2, Seat 2 ===
8System.out.println();⋯47    }48    System.out.println();49}⋯
9System.out.println();⋯47    }48    System.out.println();49}⋯
10seats[0][0] ← 1, seats[2][3] ← 1⋯21        (reserveRow + 1) + ", Seat " + (reserveCol + 1) + " ===");22    printSeating(seats);23    24    // Reserve more seats25    seats[0][0]→ 1 = 1;26    seats[2][3]→ 1 = 1;27    28    System.out.println("\n=== After Additional Reservations ===");29    printSeating(seats);30    31    // Count available seats32    int available = 0;33    for (int[] row : seats) {34        for (int seat : row) {35            if (seat == 0) available++;36        }37    }38    System.out.println("\nAvailable seats: " + available);39}4041static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {44        System.out.print((r + 1) + " ");45        for (int c = 0; c < seats[r].length; c++) {46            System.out.print(seats[r][c] == 0 ? "O " : "X ");47        }48        System.out.println();49    }⋯output
=== After Additional Reservations ===
11System.out.println();⋯47    }48    System.out.println();49}⋯
12System.out.println();⋯47    }48    System.out.println();49}⋯
13available ← 0⋯28    System.out.println("\n=== After Additional Reservations ===");29    printSeating(seats);30    31    // Count available seats32    int available→ 0 = 0;33    for (int[] row : seats) {34        for (int seat : row) {35            if (seat == 0) available++;36        }37    }38    System.out.println("\nAvailable seats: " + available);39}4041static void printSeating(int[][] seats) {42    System.out.println("  1 2 3 4");43    for (int r = 0; r < seats.length; r++) {44        System.out.print((r + 1) + " ");45        for (int c = 0; c < seats[r].length; c++) {46            System.out.print(seats[r][c] == 0 ? "O " : "X ");47        }48        System.out.println();49    }⋯
14for (int[] row : seats)pass 1 of 3⋯32int available = 0;33for (int[] row : seats) {34    for (int seat : row) {⋯
15for (int seat : row)pass 1 of 12⋯33for (int[] row : seats) {34    for (int seat1 : row) {35        if (seat == 0) available++;⋯All 12 passes — pass 1 is the card abovepassseat
11
20
30
40
50
61
70
80
90
100
110
121
16available ← 1pass 1 of 9⋯34for (int seat : row) {35    if (seat0 == 0) available→ 1++;36}⋯All 9 passes — pass 1 is the card abovepassavailable
10 → 1
21 → 2
32 → 3
43 → 4
54 → 5
65 → 6
76 → 7
87 → 8
98 → 9
17System.out.println(" Available seats: " + available);⋯37    }38    System.out.println("\nAvailable seats: " + available9);39}⋯output
Available seats: 9

All 9 passes — pass 1 is the card above
pass	`r`
1	0
2	1
3	2
4	0
5	1
6	2
7	0
8	1
9	2

36 passes — pass 1 is the card above
pass	`c`	`r`	`seats[r][c]`
1	0	0	0
2	1	0	0
3	2	0	0
4	3	0	0
5	0	1	0
6	1	1	0
7	2	1	0
8	3	1	0
9	0	2	0
⋯ 25 more passes ⋯
35	2	2	0
36	3	2	1

All 12 passes — pass 1 is the card above
pass	`seat`
1	1
2	0
3	0
4	0
5	0
6	0
7	1
8	0
9	0
10	0
11	0
12	1

All 9 passes — pass 1 is the card above
pass	`available`
1	0 → 1
2	1 → 2
3	2 → 3
4	3 → 4
5	4 → 5
6	5 → 6
7	6 → 7
8	7 → 8
9	8 → 9

All 9 passes — pass 1 is the card above
pass	`r`
1	0
2	1
3	2
4	0
5	1
6	2
7	0
8	1
9	2

36 passes — pass 1 is the card above
pass	`c`	`r`	`seats[r][c]`
1	0	0	0
2	1	0	0
3	2	0	0
4	3	0	0
5	0	1	0
6	1	1	0
7	2	1	0
8	3	1	0
9	0	2	0
⋯ 25 more passes ⋯
35	2	2	0
36	3	2	1

All 12 passes — pass 1 is the card above
pass	`seat`
1	1
2	0
3	1
4	0
5	0
6	0
7	0
8	0
9	0
10	0
11	0
12	1

All 9 passes — pass 1 is the card above
pass	`available`
1	0 → 1
2	1 → 2
3	2 → 3
4	3 → 4
5	4 → 5
6	5 → 6
7	6 → 7
8	7 → 8
9	8 → 9

All 9 passes — pass 1 is the card above
pass	`r`
1	0
2	1
3	2
4	0
5	1
6	2
7	0
8	1
9	2

36 passes — pass 1 is the card above
pass	`c`	`r`	`seats[r][c]`
1	0	0	0
2	1	0	0
3	2	0	0
4	3	0	0
5	0	1	0
6	1	1	0
7	2	1	0
8	3	1	0
9	0	2	0
⋯ 25 more passes ⋯
35	2	2	0
36	3	2	1

All 12 passes — pass 1 is the card above
pass	`seat`
1	1
2	0
3	0
4	0
5	0
6	1
7	0
8	0
9	0
10	0
11	0
12	1

All 9 passes — pass 1 is the card above
pass	`available`
1	0 → 1
2	1 → 2
3	2 → 3
4	3 → 4
5	4 → 5
6	5 → 6
7	6 → 7
8	7 → 8
9	8 → 9

Assign directly: grid[row][col] = value. Arrays are mutable.

Sum all values

Calculate a total by traversing every cell.

                            data
                            data = sales (default)data = quarterly
                        

                            SumAll.java
                        
Replay: real traced execution (multi-file project)

                            public class SumAll {
    public static void main(String[] args) {
        // Monthly sales by product (in units)
        // Rows: Products (0=Widgets, 1=Gadgets, 2=Gizmos)
        // Cols: Months (0=Jan, 1=Feb, 2=Mar)
        int[][] sales = {
            {120, 135, 150},  // Widgets
            {80, 95, 110},    // Gadgets
            {200, 180, 220}   // Gizmos
        };

        // Quarterly sales (4 products, 4 quarters)
        int[][] quarterly = {
            {1200, 1350, 1500, 1400},
            {800, 950, 1100, 1050},
            {2000, 1800, 2200, 2100},
            {500, 600, 700, 650}
        };

        int[][] data = sales;

        // Calculate total sales
        int grandTotal = 0;
        for (int row = 0; row < data.length; row++) {
            for (int col = 0; col < data[row].length; col++) {
                grandTotal += data[row][col];
            }
        }

        System.out.println("=== Sales Summary ===");
        System.out.println("Grand Total: " + grandTotal + " units");

        // Calculate row totals (per product)
        System.out.println("\n=== Per Product ===");
        String[] products = {"Widgets", "Gadgets", "Gizmos", "Sprockets"};
        for (int row = 0; row < data.length; row++) {
            int rowTotal = 0;
            for (int col = 0; col < data[row].length; col++) {
                rowTotal += data[row][col];
            }
            System.out.println(products[row] + ": " + rowTotal);
        }

        // Calculate column totals (per month/quarter)
        System.out.println("\n=== Per Period ===");
        for (int col = 0; col < data[0].length; col++) {
            int colTotal = 0;
            for (int row = 0; row < data.length; row++) {
                colTotal += data[row][col];
            }
            System.out.println("Period " + (col + 1) + ": " + colTotal);
        }
    }
}
public class SumAll {
    public static void main(String[] args) {
        // Monthly sales by product (in units)
        // Rows: Products (0=Widgets, 1=Gadgets, 2=Gizmos)
        // Cols: Months (0=Jan, 1=Feb, 2=Mar)
        int[][] sales = {
            {120, 135, 150},  // Widgets
            {80, 95, 110},    // Gadgets
            {200, 180, 220}   // Gizmos
        };

        // Quarterly sales (4 products, 4 quarters)
        int[][] quarterly = {
            {1200, 1350, 1500, 1400},
            {800, 950, 1100, 1050},
            {2000, 1800, 2200, 2100},
            {500, 600, 700, 650}
        };

        int[][] data = quarterly;

        // Calculate total sales
        int grandTotal = 0;
        for (int row = 0; row < data.length; row++) {
            for (int col = 0; col < data[row].length; col++) {
                grandTotal += data[row][col];
            }
        }

        System.out.println("=== Sales Summary ===");
        System.out.println("Grand Total: " + grandTotal + " units");

        // Calculate row totals (per product)
        System.out.println("\n=== Per Product ===");
        String[] products = {"Widgets", "Gadgets", "Gizmos", "Sprockets"};
        for (int row = 0; row < data.length; row++) {
            int rowTotal = 0;
            for (int col = 0; col < data[row].length; col++) {
                rowTotal += data[row][col];
            }
            System.out.println(products[row] + ": " + rowTotal);
        }

        // Calculate column totals (per month/quarter)
        System.out.println("\n=== Per Period ===");
        for (int col = 0; col < data[0].length; col++) {
            int colTotal = 0;
            for (int row = 0; row < data.length; row++) {
                colTotal += data[row][col];
            }
            System.out.println("Period " + (col + 1) + ": " + colTotal);
        }
    }
}

                        
1grandTotal ← 0⋯2public class SumAll {3    public static void main(String[] args) {4        // Monthly sales by product (in units)5        // Rows: Products (0=Widgets, 1=Gadgets, 2=Gizmos)6        // Cols: Months (0=Jan, 1=Feb, 2=Mar)7        int[][] sales = {     //@var=_,!8            {120, 135, 150},  // Widgets9            {80, 95, 110},    // Gadgets10            {200, 180, 220}   // Gizmos11        };12        13        // Quarterly sales (4 products, 4 quarters)14        int[][] quarterly = {  //@var=!,_15            {1200, 1350, 1500, 1400},16            {800, 950, 1100, 1050},17            {2000, 1800, 2200, 2100},18            {500, 600, 700, 650}19        };20        21        int[][] data = sales;  //@var=_,quarterly22        23        // Calculate total sales24        int grandTotal→ 0 = 0;  //?sum25        for (int row = 0; row < data.length; row++) {⋯
2for (int row = 0; row < data.length; row++)pass 1 of 3⋯24int grandTotal = 0;  //?sum25for (int row0 = 0; row < data.length3; row++) {26    for (int col = 0; col < data[row].length; col++) {⋯All 3 passes — pass 1 is the card abovepassrow
10
21
32
3grandTotal ← 120pass 1 of 9⋯25for (int row = 0; row < data.length; row++) {26    for (int col0 = 0; col < data[row].length3; col++) {27        grandTotal→ 120 += data[row][col]120;28    }⋯All 9 passes — pass 1 is the card abovepasscolrowdata[row][col]grandTotal
1001200 → 120
210135120 → 255
320150255 → 405
40180405 → 485
51195485 → 580
621110580 → 690
702200690 → 890
812180890 → 1070
9222201070 → 1290
4System.out.println("Grand Total: " + grandTotal + " units");⋯31System.out.println("=== Sales Summary ===");32System.out.println("Grand Total: " + grandTotal1290 + " units");3334// Calculate row totals (per product)35System.out.println("\n=== Per Product ===");36String[] products = {"Widgets", "Gadgets", "Gizmos", "Sprockets"};37for (int row = 0; row < data.length; row++) {⋯output=== Sales Summary ===
Grand Total: 1290 units

=== Per Product ===
5rowTotal ← 0pass 1 of 3⋯36String[] products = {"Widgets", "Gadgets", "Gizmos", "Sprockets"};37for (int row0 = 0; row < data.length3; row++) {38    int rowTotal→ 0 = 0;39    for (int col = 0; col < data[row].length; col++) {⋯All 3 passes — pass 1 is the card abovepassrowrowTotal
100
210
320
6rowTotal ← 120pass 1 of 9⋯38int rowTotal = 0;39for (int col0 = 0; col < data[row].length3; col++) {40    rowTotal→ 120 += data[row][col]120;41}⋯All 9 passes — pass 1 is the card abovepasscolrowdata[row][col]rowTotal
1001200 → 120
210135120 → 255
320150255 → 405
401800 → 80
5119580 → 175
621110175 → 285
7022000 → 200
812180200 → 380
922220380 → 600
7System.out.println(products[row] + ": " + rowTotal);⋯41    }42    System.out.println(products[row]Widgets + ": " + rowTotal405);43}⋯outputWidgets: 405values this step0row
8System.out.println(products[row] + ": " + rowTotal);⋯41    }42    System.out.println(products[row]Gadgets + ": " + rowTotal285);43}⋯outputGadgets: 285values this step1row
9System.out.println(products[row] + ": " + rowTotal);⋯41    }42    System.out.println(products[row]Gizmos + ": " + rowTotal600);43}⋯outputGizmos: 600values this step2row
10System.out.println(" === Per Period ===");⋯45// Calculate column totals (per month/quarter)46System.out.println("\n=== Per Period ===");47for (int col = 0; col < data[0].length; col++) {⋯output
=== Per Period ===
11colTotal ← 0pass 1 of 3⋯46System.out.println("\n=== Per Period ===");47for (int col0 = 0; col < data[0].length3; col++) {48    int colTotal→ 0 = 0;49    for (int row = 0; row < data.length; row++) {⋯All 3 passes — pass 1 is the card abovepasscolcolTotal
100
210
320
12colTotal ← 120pass 1 of 9⋯48int colTotal = 0;49for (int row0 = 0; row < data.length3; row++) {50    colTotal→ 120 += data[row][col]120;51}⋯All 9 passes — pass 1 is the card abovepassrowdata[row][col]colcolTotal
1012000 → 120
21800120 → 200
322000200 → 400
4013510 → 135
51951135 → 230
621801230 → 410
7015020 → 150
811102150 → 260
922202260 → 480
13System.out.println("Period " + (col + 1) + ": " + colTotal);⋯51    }52    System.out.println("Period " + (col0 + 1) + ": " + colTotal400);53}⋯outputPeriod 1: 400
14System.out.println("Period " + (col + 1) + ": " + colTotal);⋯51    }52    System.out.println("Period " + (col1 + 1) + ": " + colTotal410);53}⋯outputPeriod 2: 410
15System.out.println("Period " + (col + 1) + ": " + colTotal);⋯51    }52    System.out.println("Period " + (col2 + 1) + ": " + colTotal480);53}⋯outputPeriod 3: 480
1grandTotal ← 01public class SumAll {2    public static void main(String[] args) {3        // Monthly sales by product (in units)4        // Rows: Products (0=Widgets, 1=Gadgets, 2=Gizmos)5        // Cols: Months (0=Jan, 1=Feb, 2=Mar)6        int[][] sales = {7            {120, 135, 150},  // Widgets8            {80, 95, 110},    // Gadgets9            {200, 180, 220}   // Gizmos10        };11        12        // Quarterly sales (4 products, 4 quarters)13        int[][] quarterly = {14            {1200, 1350, 1500, 1400},15            {800, 950, 1100, 1050},16            {2000, 1800, 2200, 2100},17            {500, 600, 700, 650}18        };19        20        int[][] data = quarterly;21        22        // Calculate total sales23        int grandTotal→ 0 = 0;24        for (int row = 0; row < data.length; row++) {⋯
2for (int row = 0; row < data.length; row++)pass 1 of 4⋯23int grandTotal = 0;24for (int row0 = 0; row < data.length4; row++) {25    for (int col = 0; col < data[row].length; col++) {⋯All 4 passes — pass 1 is the card abovepassrow
10
21
32
43
3grandTotal ← 1200pass 1 of 16⋯24for (int row = 0; row < data.length; row++) {25    for (int col0 = 0; col < data[row].length4; col++) {26        grandTotal→ 1200 += data[row][col]1200;27    }⋯16 passes — pass 1 is the card abovepasscolrowdata[row][col]grandTotal
10012000 → 1200
21013501200 → 2550
32015002550 → 4050
43014004050 → 5450
5018005450 → 6250
6119506250 → 7200
72111007200 → 8300
83110508300 → 9350
90220009350 → 11350
⋯ 5 more passes ⋯
152370018550 → 19250
163365019250 → 19900
4System.out.println("Grand Total: " + grandTotal + " units");⋯30System.out.println("=== Sales Summary ===");31System.out.println("Grand Total: " + grandTotal19900 + " units");3233// Calculate row totals (per product)34System.out.println("\n=== Per Product ===");35String[] products = {"Widgets", "Gadgets", "Gizmos", "Sprockets"};36for (int row = 0; row < data.length; row++) {⋯output=== Sales Summary ===
Grand Total: 19900 units

=== Per Product ===
5rowTotal ← 0pass 1 of 4⋯35String[] products = {"Widgets", "Gadgets", "Gizmos", "Sprockets"};36for (int row0 = 0; row < data.length4; row++) {37    int rowTotal→ 0 = 0;38    for (int col = 0; col < data[row].length; col++) {⋯All 4 passes — pass 1 is the card abovepassrowrowTotal
100
210
320
430
6rowTotal ← 1200pass 1 of 16⋯37int rowTotal = 0;38for (int col0 = 0; col < data[row].length4; col++) {39    rowTotal→ 1200 += data[row][col]1200;40}⋯16 passes — pass 1 is the card abovepasscolrowdata[row][col]rowTotal
10012000 → 1200
21013501200 → 2550
32015002550 → 4050
43014004050 → 5450
5018000 → 800
611950800 → 1750
72111001750 → 2850
83110502850 → 3900
90220000 → 2000
⋯ 5 more passes ⋯
15237001100 → 1800
16336501800 → 2450
7System.out.println(products[row] + ": " + rowTotal);⋯40    }41    System.out.println(products[row]Widgets + ": " + rowTotal5450);42}⋯outputWidgets: 5450values this step0row
8System.out.println(products[row] + ": " + rowTotal);⋯40    }41    System.out.println(products[row]Gadgets + ": " + rowTotal3900);42}⋯outputGadgets: 3900values this step1row
9System.out.println(products[row] + ": " + rowTotal);⋯40    }41    System.out.println(products[row]Gizmos + ": " + rowTotal8100);42}⋯outputGizmos: 8100values this step2row
10System.out.println(products[row] + ": " + rowTotal);⋯40    }41    System.out.println(products[row]Sprockets + ": " + rowTotal2450);42}⋯outputSprockets: 2450values this step3row
11System.out.println(" === Per Period ===");⋯44// Calculate column totals (per month/quarter)45System.out.println("\n=== Per Period ===");46for (int col = 0; col < data[0].length; col++) {⋯output
=== Per Period ===
12colTotal ← 0pass 1 of 4⋯45System.out.println("\n=== Per Period ===");46for (int col0 = 0; col < data[0].length4; col++) {47    int colTotal→ 0 = 0;48    for (int row = 0; row < data.length; row++) {⋯All 4 passes — pass 1 is the card abovepasscolcolTotal
100
210
320
430
13colTotal ← 1200pass 1 of 16⋯47int colTotal = 0;48for (int row0 = 0; row < data.length4; row++) {49    colTotal→ 1200 += data[row][col]1200;50}⋯16 passes — pass 1 is the card abovepassrowdata[row][col]colcolTotal
10120000 → 1200
2180001200 → 2000
32200002000 → 4000
4350004000 → 4500
50135010 → 1350
6195011350 → 2300
72180012300 → 4100
8360014100 → 4700
90150020 → 1500
⋯ 5 more passes ⋯
152210032450 → 4550
16365034550 → 5200
14System.out.println("Period " + (col + 1) + ": " + colTotal);⋯50    }51    System.out.println("Period " + (col0 + 1) + ": " + colTotal4500);52}⋯outputPeriod 1: 4500
15System.out.println("Period " + (col + 1) + ": " + colTotal);⋯50    }51    System.out.println("Period " + (col1 + 1) + ": " + colTotal4700);52}⋯outputPeriod 2: 4700
16System.out.println("Period " + (col + 1) + ": " + colTotal);⋯50    }51    System.out.println("Period " + (col2 + 1) + ": " + colTotal5500);52}⋯outputPeriod 3: 5500
17System.out.println("Period " + (col + 1) + ": " + colTotal);⋯50    }51    System.out.println("Period " + (col3 + 1) + ": " + colTotal5200);52}⋯outputPeriod 4: 5200

All 3 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2

All 9 passes — pass 1 is the card above
pass	`col`	`row`	`data[row][col]`	`grandTotal`
1	0	0	120	0 → 120
2	1	0	135	120 → 255
3	2	0	150	255 → 405
4	0	1	80	405 → 485
5	1	1	95	485 → 580
6	2	1	110	580 → 690
7	0	2	200	690 → 890
8	1	2	180	890 → 1070
9	2	2	220	1070 → 1290

All 3 passes — pass 1 is the card above
pass	`row`	`rowTotal`
1	0	0
2	1	0
3	2	0

All 9 passes — pass 1 is the card above
pass	`col`	`row`	`data[row][col]`	`rowTotal`
1	0	0	120	0 → 120
2	1	0	135	120 → 255
3	2	0	150	255 → 405
4	0	1	80	0 → 80
5	1	1	95	80 → 175
6	2	1	110	175 → 285
7	0	2	200	0 → 200
8	1	2	180	200 → 380
9	2	2	220	380 → 600

All 3 passes — pass 1 is the card above
pass	`col`	`colTotal`
1	0	0
2	1	0
3	2	0

All 9 passes — pass 1 is the card above
pass	`row`	`data[row][col]`	`col`	`colTotal`
1	0	120	0	0 → 120
2	1	80	0	120 → 200
3	2	200	0	200 → 400
4	0	135	1	0 → 135
5	1	95	1	135 → 230
6	2	180	1	230 → 410
7	0	150	2	0 → 150
8	1	110	2	150 → 260
9	2	220	2	260 → 480

All 4 passes — pass 1 is the card above
pass	`row`
1	0
2	1
3	2
4	3

16 passes — pass 1 is the card above
pass	`col`	`row`	`data[row][col]`	`grandTotal`
1	0	0	1200	0 → 1200
2	1	0	1350	1200 → 2550
3	2	0	1500	2550 → 4050
4	3	0	1400	4050 → 5450
5	0	1	800	5450 → 6250
6	1	1	950	6250 → 7200
7	2	1	1100	7200 → 8300
8	3	1	1050	8300 → 9350
9	0	2	2000	9350 → 11350
⋯ 5 more passes ⋯
15	2	3	700	18550 → 19250
16	3	3	650	19250 → 19900

All 4 passes — pass 1 is the card above
pass	`row`	`rowTotal`
1	0	0
2	1	0
3	2	0
4	3	0

16 passes — pass 1 is the card above
pass	`col`	`row`	`data[row][col]`	`rowTotal`
1	0	0	1200	0 → 1200
2	1	0	1350	1200 → 2550
3	2	0	1500	2550 → 4050
4	3	0	1400	4050 → 5450
5	0	1	800	0 → 800
6	1	1	950	800 → 1750
7	2	1	1100	1750 → 2850
8	3	1	1050	2850 → 3900
9	0	2	2000	0 → 2000
⋯ 5 more passes ⋯
15	2	3	700	1100 → 1800
16	3	3	650	1800 → 2450

All 4 passes — pass 1 is the card above
pass	`col`	`colTotal`
1	0	0
2	1	0
3	2	0
4	3	0

16 passes — pass 1 is the card above
pass	`row`	`data[row][col]`	`col`	`colTotal`
1	0	1200	0	0 → 1200
2	1	800	0	1200 → 2000
3	2	2000	0	2000 → 4000
4	3	500	0	4000 → 4500
5	0	1350	1	0 → 1350
6	1	950	1	1350 → 2300
7	2	1800	1	2300 → 4100
8	3	600	1	4100 → 4700
9	0	1500	2	0 → 1500
⋯ 5 more passes ⋯
15	2	2100	3	2450 → 4550
16	3	650	3	4550 → 5200

Use nested loops: outer loop for rows, inner loop for columns.

row-major Process row by row: `for (row) { for (col) { grid[row][col] } }`

Find a value's position

Search for a value and return its row/column.

                            targetSeat
                            targetSeat = "C3" (default)targetSeat = "Z9"
                        

                            FindPosition.java
                        
Replay: real traced execution (multi-file project)

                            public class FindPosition {
    public static void main(String[] args) {
        // Movie theater seat map with seat IDs
        String[][] seatMap = {
            {"A1", "A2", "A3", "A4", "A5"},
            {"B1", "B2", "B3", "B4", "B5"},
            {"C1", "C2", "C3", "C4", "C5"},
            {"D1", "D2", "D3", "D4", "D5"}
        };

        // Find this seat
        String targetSeat = "C3";

        // Search for the seat
        int foundRow = -1;
        int foundCol = -1;

        for (int row = 0; row < seatMap.length; row++) {
            for (int col = 0; col < seatMap[row].length; col++) {
                if (seatMap[row][col].equals(targetSeat)) {
                    foundRow = row;
                    foundCol = col;
                    break;  // Found it, exit inner loop
                }
            }
            if (foundRow != -1) break;  // Exit outer loop too
        }

        System.out.println("=== Seat Finder ===");
        System.out.println("Looking for seat: " + targetSeat);

        if (foundRow != -1) {
            System.out.println("Found at position:");
            System.out.println("  Row index: " + foundRow + " (Row " + (foundRow + 1) + ")");
            System.out.println("  Col index: " + foundCol + " (Seat " + (foundCol + 1) + ")");

            // Calculate walking directions
            System.out.println("\nDirections: Walk to row " + (foundRow + 1) +
                ", then count " + (foundCol + 1) + " seat(s) from the left.");
        } else {
            System.out.println("Seat not found!");
        }

        // Show the map with target highlighted
        System.out.println("\n=== Seat Map ===");
        for (int row = 0; row < seatMap.length; row++) {
            for (int col = 0; col < seatMap[row].length; col++) {
                if (row == foundRow && col == foundCol) {
                    System.out.print("[" + seatMap[row][col] + "]\t");
                } else {
                    System.out.print(" " + seatMap[row][col] + " \t");
                }
            }
            System.out.println();
        }
    }
}
public class FindPosition {
    public static void main(String[] args) {
        // Movie theater seat map with seat IDs
        String[][] seatMap = {
            {"A1", "A2", "A3", "A4", "A5"},
            {"B1", "B2", "B3", "B4", "B5"},
            {"C1", "C2", "C3", "C4", "C5"},
            {"D1", "D2", "D3", "D4", "D5"}
        };

        // Find this seat
        String targetSeat = "Z9";

        // Search for the seat
        int foundRow = -1;
        int foundCol = -1;

        for (int row = 0; row < seatMap.length; row++) {
            for (int col = 0; col < seatMap[row].length; col++) {
                if (seatMap[row][col].equals(targetSeat)) {
                    foundRow = row;
                    foundCol = col;
                    break;  // Found it, exit inner loop
                }
            }
            if (foundRow != -1) break;  // Exit outer loop too
        }

        System.out.println("=== Seat Finder ===");
        System.out.println("Looking for seat: " + targetSeat);

        if (foundRow != -1) {
            System.out.println("Found at position:");
            System.out.println("  Row index: " + foundRow + " (Row " + (foundRow + 1) + ")");
            System.out.println("  Col index: " + foundCol + " (Seat " + (foundCol + 1) + ")");

            // Calculate walking directions
            System.out.println("\nDirections: Walk to row " + (foundRow + 1) +
                ", then count " + (foundCol + 1) + " seat(s) from the left.");
        } else {
            System.out.println("Seat not found!");
        }

        // Show the map with target highlighted
        System.out.println("\n=== Seat Map ===");
        for (int row = 0; row < seatMap.length; row++) {
            for (int col = 0; col < seatMap[row].length; col++) {
                if (row == foundRow && col == foundCol) {
                    System.out.print("[" + seatMap[row][col] + "]\t");
                } else {
                    System.out.print(" " + seatMap[row][col] + " \t");
                }
            }
            System.out.println();
        }
    }
}

                        
1targetSeat ← C3, foundRow ← -1, foundCol ← -1⋯2public class FindPosition {3    public static void main(String[] args) {4        // Movie theater seat map with seat IDs5        String[][] seatMap = {6            {"A1", "A2", "A3", "A4", "A5"},7            {"B1", "B2", "B3", "B4", "B5"},8            {"C1", "C2", "C3", "C4", "C5"},9            {"D1", "D2", "D3", "D4", "D5"}10        };11        12        // Find this seat13        String targetSeat→ C3 = "C3";  //@var=_,Z914        15        // Search for the seat16        int foundRow→ -1 = -1;  //?found17        int foundCol→ -1 = -1;⋯
2for (int row = 0; row < seatMap.length; row++)pass 1 of 3⋯19for (int row0 = 0; row < seatMap.length4; row++) {20    for (int col = 0; col < seatMap[row].length; col++) {⋯All 3 passes — pass 1 is the card abovepassrowseatMap[row][col]coltargetSeatfoundRowfoundCol
10—————
21—————
32C32C322
3for (int col = 0; col < seatMap[row].length; col++)pass 1 of 13⋯19for (int row = 0; row < seatMap.length; row++) {20    for (int col0 = 0; col < seatMap[row].length5; col++) {21        if (seatMap[row][col].equals(targetSeat)) {⋯13 passes — pass 1 is the card abovepasscolrowseatMap[row][col]targetSeatfoundRowfoundCol
100————
210————
320————
430————
540————
601————
711————
821————
931————
⋯ 2 more passes ⋯
1212————
1322C3C322
4foundRow ← 2, foundCol ← 2⋯20for (int col = 0; col < seatMap[row].length; col++) {21    if (seatMap[row][col]C3.equals(targetSeatC3)) {22        foundRow→ 2 = row2;23        foundCol→ 2 = col2;24        break;  // Found it, exit inner loop25    }⋯
5if (foundRow != -1)⋯26    }27    if (foundRow2 != -1) break;  // Exit outer loop too28}⋯
6System.out.println("Looking for seat: " + targetSeat);⋯30System.out.println("=== Seat Finder ===");31System.out.println("Looking for seat: " + targetSeatC3);⋯output=== Seat Finder ===
Looking for seat: C3
7if (foundRow != -1)⋯33if (foundRow2 != -1) {34    System.out.println("Found at position:");35    System.out.println("  Row index: " + foundRow2 + " (Row " + (foundRow + 1) + ")");36    System.out.println("  Col index: " + foundCol2 + " (Seat " + (foundCol + 1) + ")");37    38    // Calculate walking directions39    System.out.println("\nDirections: Walk to row " + (foundRow2 + 1) + 40        ", then count " + (foundCol2 + 1) + " seat(s) from the left.");41} else {⋯outputFound at position:
  Row index: 2 (Row 3)
  Col index: 2 (Seat 3)

Directions: Walk to row 3, then count 3 seat(s) from the left.
8System.out.println(" === Seat Map ===");⋯45// Show the map with target highlighted46System.out.println("\n=== Seat Map ===");47for (int row = 0; row < seatMap.length; row++) {⋯output
=== Seat Map ===
9for (int row = 0; row < seatMap.length; row++)pass 1 of 4⋯46System.out.println("\n=== Seat Map ===");47for (int row0 = 0; row < seatMap.length4; row++) {48    for (int col = 0; col < seatMap[row].length; col++) {⋯All 4 passes — pass 1 is the card abovepassrowfoundRowcolfoundColseatMap[row][col]
10————
21————
32222C3
43————
10for (int col = 0; col < seatMap[row].length; col++)pass 1 of 20⋯47for (int row = 0; row < seatMap.length; row++) {48    for (int col0 = 0; col < seatMap[row].length5; col++) {49        if (row == foundRow && col == foundCol) {⋯20 passes — pass 1 is the card abovepasscolrowfoundRowfoundColseatMap[row][col]
100———
210———
320———
430———
540———
601———
711———
821———
931———
⋯ 9 more passes ⋯
1933———
2043———
11elsepass 1 of 19⋯50    System.out.print("[" + seatMap[row][col] + "]\t");51} else {52    System.out.print(" " + seatMap[row][col]A1 + " \t");53}⋯output A1 	19 passes — pass 1 is the card abovepassseatMap[row][col]rowcolfoundRowfoundCol
1A100——
2A201——
3A302——
4A403——
5A504——
6B110——
7B211——
8B312——
9B413——
⋯ 8 more passes ⋯
18D433——
19D534——
12System.out.println();⋯54    }55    System.out.println();56}⋯
13System.out.println();⋯54    }55    System.out.println();56}⋯
14if (row == foundRow && col == foundCol)⋯48for (int col = 0; col < seatMap[row].length; col++) {49    if (row2 == foundRow2 && col2 == foundCol2) {50        System.out.print("[" + seatMap[row][col]C3 + "]\t");51    } else {⋯output[C3]	
15System.out.println();⋯54    }55    System.out.println();56}⋯
16System.out.println();⋯54    }55    System.out.println();56}⋯
1targetSeat ← Z9, foundRow ← -1, foundCol ← -11public class FindPosition {2    public static void main(String[] args) {3        // Movie theater seat map with seat IDs4        String[][] seatMap = {5            {"A1", "A2", "A3", "A4", "A5"},6            {"B1", "B2", "B3", "B4", "B5"},7            {"C1", "C2", "C3", "C4", "C5"},8            {"D1", "D2", "D3", "D4", "D5"}9        };10        11        // Find this seat12        String targetSeat→ Z9 = "Z9";13        14        // Search for the seat15        int foundRow→ -1 = -1;16        int foundCol→ -1 = -1;⋯
2for (int row = 0; row < seatMap.length; row++)pass 1 of 4⋯18for (int row0 = 0; row < seatMap.length4; row++) {19    for (int col = 0; col < seatMap[row].length; col++) {⋯All 4 passes — pass 1 is the card abovepassrow
10
21
32
43
3for (int col = 0; col < seatMap[row].length; col++)pass 1 of 20⋯18for (int row = 0; row < seatMap.length; row++) {19    for (int col0 = 0; col < seatMap[row].length5; col++) {20        if (seatMap[row][col].equals(targetSeat)) {⋯20 passes — pass 1 is the card abovepasscolrow
100
210
320
430
540
601
711
821
931
⋯ 9 more passes ⋯
1933
2043
4System.out.println("Looking for seat: " + targetSeat);⋯29System.out.println("=== Seat Finder ===");30System.out.println("Looking for seat: " + targetSeatZ9);⋯output=== Seat Finder ===
Looking for seat: Z9
5else⋯39        ", then count " + (foundCol + 1) + " seat(s) from the left.");40} else {41    System.out.println("Seat not found!");42}⋯outputSeat not found!
6System.out.println(" === Seat Map ===");⋯44// Show the map with target highlighted45System.out.println("\n=== Seat Map ===");46for (int row = 0; row < seatMap.length; row++) {⋯output
=== Seat Map ===
7for (int row = 0; row < seatMap.length; row++)pass 1 of 4⋯45System.out.println("\n=== Seat Map ===");46for (int row0 = 0; row < seatMap.length4; row++) {47    for (int col = 0; col < seatMap[row].length; col++) {⋯All 4 passes — pass 1 is the card abovepassrow
10
21
32
43
8for (int col = 0; col < seatMap[row].length; col++)pass 1 of 20⋯46for (int row = 0; row < seatMap.length; row++) {47    for (int col0 = 0; col < seatMap[row].length5; col++) {48        if (row == foundRow && col == foundCol) {⋯20 passes — pass 1 is the card abovepasscolrow
100
210
320
430
540
601
711
821
931
⋯ 9 more passes ⋯
1933
2043
9elsepass 1 of 20⋯49    System.out.print("[" + seatMap[row][col] + "]\t");50} else {51    System.out.print(" " + seatMap[row][col]A1 + " \t");52}⋯output A1 	20 passes — pass 1 is the card abovepassseatMap[row][col]rowcol
1A100
2A201
3A302
4A403
5A504
6B110
7B211
8B312
9B413
⋯ 9 more passes ⋯
19D433
20D534
10System.out.println();⋯53    }54    System.out.println();55}⋯
11System.out.println();⋯53    }54    System.out.println();55}⋯
12System.out.println();⋯53    }54    System.out.println();55}⋯
13System.out.println();⋯53    }54    System.out.println();55}⋯

All 3 passes — pass 1 is the card above
pass	`row`	`seatMap[row][col]`	`col`	`targetSeat`	`foundRow`	`foundCol`
1	0	—	—	—	—	—
2	1	—	—	—	—	—
3	2	C3	2	C3	2	2

13 passes — pass 1 is the card above
pass	`col`	`row`	`seatMap[row][col]`	`targetSeat`	`foundRow`	`foundCol`
1	0	0	—	—	—	—
2	1	0	—	—	—	—
3	2	0	—	—	—	—
4	3	0	—	—	—	—
5	4	0	—	—	—	—
6	0	1	—	—	—	—
7	1	1	—	—	—	—
8	2	1	—	—	—	—
9	3	1	—	—	—	—
⋯ 2 more passes ⋯
12	1	2	—	—	—	—
13	2	2	C3	C3	2	2

All 4 passes — pass 1 is the card above
pass	`row`	`foundRow`	`col`	`foundCol`	`seatMap[row][col]`
1	0	—	—	—	—
2	1	—	—	—	—
3	2	2	2	2	C3
4	3	—	—	—	—

20 passes — pass 1 is the card above
pass	`col`	`row`	`foundRow`	`foundCol`	`seatMap[row][col]`
1	0	0	—	—	—
2	1	0	—	—	—
3	2	0	—	—	—
4	3	0	—	—	—
5	4	0	—	—	—
6	0	1	—	—	—
7	1	1	—	—	—
8	2	1	—	—	—
9	3	1	—	—	—
⋯ 9 more passes ⋯
19	3	3	—	—	—
20	4	3	—	—	—

19 passes — pass 1 is the card above
pass	`seatMap[row][col]`	`row`	`col`	`foundRow`	`foundCol`
1	A1	0	0	—	—
2	A2	0	1	—	—
3	A3	0	2	—	—
4	A4	0	3	—	—
5	A5	0	4	—	—
6	B1	1	0	—	—
7	B2	1	1	—	—
8	B3	1	2	—	—
9	B4	1	3	—	—
⋯ 8 more passes ⋯
18	D4	3	3	—	—
19	D5	3	4	—	—

Return early when found. Return special value (-1, -1) if not found.

Exercise: JaggedArray.java

Explore jagged arrays where rows have different lengths