PHP Manual
PrevChapter 10. OperatorsNext

Incrementing/Decrementing Operators

PHP supports C-style pre- and post-increment and decrement operators.

Table 10-5. Increment/decrement Operators

ExampleNameEffect
++$aPre-incrementIncrements $a by one, then returns $a.
$a++Post-incrementReturns $a, then increments $a by one.
--$aPre-decrementDecrements $a by one, then returns $a.
$a--Post-decrementReturns $a, then decrements $a by one.

Here's a simple example script: 

<?php
echo "<h3&gt;Postincrement</h3&gt;";
$a = 5;
echo "Should be 5: " . $a++ . "<br>\n";
echo "Should be 6: " . $a . "<br>\n";

echo "<h3>Preincrement</h3>";
$a = 5;
echo "Should be 6: " . ++$a . "<br>\n";
echo "Should be 6: " . $a . "<br>\n";

echo "<h3>Postdecrement</h3>";
$a = 5;
echo "Should be 5: " . $a-- . "<br>\n";
echo "Should be 4: " . $a . "<br>\n";

echo "<h3>Predecrement</h3>";
$a = 5;
echo "Should be 4: " . --$a . "<br>\n";
echo "Should be 4: " . $a . "<br>\n";
?>

PrevHomeNext
Execution OperatorsUpLogical Operators