Incremental Assignment (+=) Expression

Summary

Increment the value of a variable.

Syntax

variable += expression

Parameters

variable: The variable, property, or array element to update.
expression: Any legal expression.

Description

For numeric variables, the += operator computes the value of the expression on the right, and then adds it to the variable, property, or array element on the left. The expression on the right is evaluated prior to assignment:

int x = 2;
x += 3 * x + 5; // x is assigned the value 13

The += operator is equivalent to the + operator with the left-hand side being the variable, property, or array element to modify and the right-hand side being the expression to add. Therefore, the following expressions are equivalent:

x += 5;    // Equivalent to x = x + 5
x = x + 5; // Equivalent to x += 5

For simply adding the value 1 (one), see the increment expression.

Examples

Basic Usage

import System;
 
int x = 1;
Console.log(x); // 1
x += 10;
Console.log(x); // 11