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Chapter 10. Operators |
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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∓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";
?>
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