The decrement operator (--) decrements its operand by 1. The decrement operator can appear before or after its operand:

-- var
var --

Where:

var

An expression that denotes a storage location or a property or an indexer.

Remarks

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).

Example

// cs_operator_decrement.cs
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);
   }
}

Output

0.5
1.5
0.5

See Also

C# Operators | 7.5.9 Postfix increment and decrement operators | 7.6.5 Prefix increment and decrement operators