What does the += operator do? « slightlymore

June 13, 2009
Posted by Clinton Montague

What does the += operator do?

The += operator is a simplified way of writing I want to increase the variable by a certain value. It’s called the addition-assignment operator.

Examples

$i = 10;
$i+=1;
echo $i; // outputs 11;
 
$i = 10;
$i+=5;
echo $i; // outputs 15
 
$i=10;
$i+= -10;
echo $i; // output 0 (since 10 + (-10) is the same as 10-10);
 
$i=10;
$i+=$i;
echo $i; // output 20;

Find out more

MSDN page about the addition assignment for JScript
Google search for “addition-assignment”
A post by me: Operator precedence – what does (i=1)*i-- - --i*(i=-3)*i++ + ++i equal and why? (not for beginners)
A similar FQG – What does the -= operator do?

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1 Comments

Loryn
September 20, 2011

Call me wind bceuase I am absolutely blown away.

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