Data Types

Strings and Chars

A string stores text, while a char stores one character.

string A string is a sequence of characters.

Strings and Chars

word
StringsChars.cs
Replay: real traced execution (multi-file project)
using System;

class Program
{
    static void Main()
    {
        string word = "code";
        char first = word[0];
        int length = word.Length;

        Console.WriteLine($"word={word}");
        Console.WriteLine($"first={first}");
        Console.WriteLine($"length={length}");
    }
}

using System;

class Program
{
    static void Main()
    {
        string word = "data";
        char first = word[0];
        int length = word.Length;

        Console.WriteLine($"word={word}");
        Console.WriteLine($"first={first}");
        Console.WriteLine($"length={length}");
    }
}

using System;

class Program
{
    static void Main()
    {
        string word = "trace";
        char first = word[0];
        int length = word.Length;

        Console.WriteLine($"word={word}");
        Console.WriteLine($"first={first}");
        Console.WriteLine($"length={length}");
    }
}

  1. word ← code, first ← c, length ← 4

    4{5    static void Main()6    {7        string word→ code = "code"; //@word="data", "trace"8        char first→ c = word[0]c;9        int length→ 4 = word.Length4;1011        Console.WriteLine($"word={wordcode}");12        Console.WriteLine($"first={firstc}");13        Console.WriteLine($"length={length4}");14    }
    outputword=code
first=c
length=4

  1. word ← data, first ← d, length ← 4

    4{5    static void Main()6    {7        string word→ data = "data";8        char first→ d = word[0]d;9        int length→ 4 = word.Length4;1011        Console.WriteLine($"word={worddata}");12        Console.WriteLine($"first={firstd}");13        Console.WriteLine($"length={length4}");14    }
    outputword=data
first=d
length=4

  1. word ← trace, first ← t, length ← 5

    4{5    static void Main()6    {7        string word→ trace = "trace";8        char first→ t = word[0]t;9        int length→ 5 = word.Length5;1011        Console.WriteLine($"word={wordtrace}");12        Console.WriteLine($"first={firstt}");13        Console.WriteLine($"length={length5}");14    }
    outputword=trace
first=t
length=5

Follow the Text

  1. word starts as code.
  2. first = word[0] reads c.
  3. length = word.Length is 4.
  4. The program prints word=code, first=c, and length=4. | word | first | length | | --- | --- | --- | | code | c | 4 | | data | d | 4 | | trace | t | 5 |

Exercise: StringsChars.cs

Reproduce first=c and length=4, then use words data and trace to predict each first character and length.