byte + byte = int… why?

Question

Looking at this C# code:

byte x = 1;
byte y = 2;
byte z = x + y; // ERROR: Cannot implicitly convert type \'int\' to \'byte\'

The result of

Answer 1

From .NET Framework code:

// bytes
private static object AddByte(byte Left, byte Right)
{
    short num = (short) (Left + Right);
    if (num > 0xff)
    {
        return num;
    }
    return (byte) num;
}

// shorts (int16)
private static object AddInt16(short Left, short Right)
{
    int num = Left + Right;
    if ((num <= 0x7fff) && (num >= -32768))
    {
        return (short) num;
    }
    return num;
}

Simplify with .NET 3.5 and above:

public static class Extensions 
{
    public static byte Add(this byte a, byte b)
    {
        return (byte)(a + b);
    }
}

now you can do:

byte a = 1, b = 2, c;
c = a.Add(b);