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# Incrementing/Decrementing Operators

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

Table 10-4. Increment/decrement Operators

example | name | effect
--- | --- | ---
++$a | Pre-increment | Increments $a by one, then returns $a.
$a++ | Post-increment | Returns $a, then increments $a by one.
--$a | Pre-decrement | Decrements $a by one, then returns $a.
$a-- | Post-decrement | Returns $a, then decrements $a by one.

Here's a simple example script:

    <?php
    echo "<h3>Postincrement</h3>";
    $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";
    ?>

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