Data Types

Primitive Types

C# primitive numeric types store whole numbers, decimal values, and simple calculations.

primitive type A primitive type is a built-in type such as `int`, `double`, or `bool`.

Primitive Types

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

class Program
{
    static void Main()
    {
        int quantity = 3;
        double price = 2.50;
        double total = quantity * price;

        Console.WriteLine($"quantity={quantity}");
        Console.WriteLine($"price={price}");
        Console.WriteLine($"total={total}");
    }
}

using System;

class Program
{
    static void Main()
    {
        int quantity = 1;
        double price = 2.50;
        double total = quantity * price;

        Console.WriteLine($"quantity={quantity}");
        Console.WriteLine($"price={price}");
        Console.WriteLine($"total={total}");
    }
}

using System;

class Program
{
    static void Main()
    {
        int quantity = 5;
        double price = 2.50;
        double total = quantity * price;

        Console.WriteLine($"quantity={quantity}");
        Console.WriteLine($"price={price}");
        Console.WriteLine($"total={total}");
    }
}

  1. quantity ← 3, price ← 2.5, total ← 7.5

    4{5    static void Main()6    {7        int quantity→ 3 = 3; //@quantity=1, 58        double price→ 2.5 = 2.50;9        double total→ 7.5 = quantity3 * price2.5;1011        Console.WriteLine($"quantity={quantity3}");12        Console.WriteLine($"price={price2.5}");13        Console.WriteLine($"total={total7.5}");14    }
    outputquantity=3
price=2.5
total=7.5

  1. quantity ← 1, price ← 2.5, total ← 2.5

    4{5    static void Main()6    {7        int quantity→ 1 = 1;8        double price→ 2.5 = 2.50;9        double total→ 2.5 = quantity1 * price2.5;1011        Console.WriteLine($"quantity={quantity1}");12        Console.WriteLine($"price={price2.5}");13        Console.WriteLine($"total={total2.5}");14    }
    outputquantity=1
price=2.5
total=2.5

  1. quantity ← 5, price ← 2.5, total ← 12.5

    4{5    static void Main()6    {7        int quantity→ 5 = 5;8        double price→ 2.5 = 2.50;9        double total→ 12.5 = quantity5 * price2.5;1011        Console.WriteLine($"quantity={quantity5}");12        Console.WriteLine($"price={price2.5}");13        Console.WriteLine($"total={total12.5}");14    }
    outputquantity=5
price=2.5
total=12.5

Follow the Values

  1. quantity starts at 3.
  2. price is 2.50.
  3. total = quantity * price.
  4. The default total is 7.5.
  5. The program prints quantity=3, price=2.5, and total=7.5. | quantity | price | total | | --- | --- | --- | | 1 | 2.5 | 2.5 | | 3 | 2.5 | 7.5 | | 5 | 2.5 | 12.5 |

Exercise: PrimitiveTypes.cs

Reproduce total=7.5, then use quantity 1 and 5 to predict each total.