Question

If i have some code like the following:

short myShortA = 54;
short myShortB = 12;
short myShortC = (short)(myShortA - myShortB);

Both operands are shorts and it’s going into a short so why do i have to cast it?

Answer 1

Because there’s no “short – short” operator. Both operands are promoted to int.

From section 7.7.5 of the C# 3 spec:

The predefined subtraction operators
are listed below. The operators all
subtract y from x.

• Integer subtraction:

  int operator –(int x, int y);
  uint operator –(uint x, uint y);
  long operator –(long x, long y); 
  ulong operator –(ulong x, ulong y);
  

  In a checked context, if the difference is
  outside the range of the result type,
  a System.OverflowException is thrown.

(And then there’s floating point subtraction.)