The subtraction assignment operator.

lhs -= expr

Where:

lhs

A storage location, property, or indexer.

expr

An expression.

Remarks

An expression using the -= assignment operator, such as

x -= y

is equivalent to

x = x - y

except that x is only evaluated once. The meaning of the - operator is dependent on the types of x and y (subtraction for numeric operands, delegate removal for delegate operands, and so forth).

The -= operator cannot be overloaded directly, but user-defined types can overload the - operator (see operator).

Example

// cs_operator_subtraction_assignment.cs
using System;
class Test 
{
   public static void Main() 
   {
      int a = 5;
      a -= 6;
      Console.WriteLine(a);
   }
}

Output

-1

See Also

C# Operators | 7.13 Assignment operators