+= Operator
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+= Operator

The addition 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 (addition for numeric operands, concatenation for string operands, and so forth).

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

Example

// cs_operator_addition_assignment.cs
using System;
class Test 
{
   public static void Main() 
   {
      int a = 5;
      a += 6;
      Console.WriteLine(a);
      string s = "Micro";
      s += "soft";
      Console.WriteLine(s);
   }
}

Output

11
Microsoft

See Also

C# Operators | 7.13 Assignment operators

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