The decrement operator (--) decrements its operand by 1. The decrement operator can appear before or after its operand:
-- var var --
The first form is a prefix decrement operation. The result of the operation is the value of the operand after it has been decremented.
The second form is a postfix decrement operation. The result of the operation is the value of the operand before it has been decremented.
Numeric and enumeration types have predefined decrement operators. User-defined types can overload the -- operator (see operator).
using System; class Test { public static void Main() { double x; x = 1.5; Console.WriteLine(--x); x = 1.5; Console.WriteLine(x--); Console.WriteLine(x); } }
0.5 1.5 0.5
C# Operators | CLR 7.5.10 Postfix decrement operator | CLR 7.6.8 Prefix decrement operator