Prints all combinations of n-pairs of balanced parentheses using PHP

balanced-parentheses.php

<?php
function printbraces($n) {
	if($n>0) {
		start_printing("", $n, $n);
	}
}
function start_printing($s, $o, $c) {
	if($o > $c)
		return;
	if($o == 0 && $c == 0){
		echo $s . "<br/>";
		return;
	}
	if($o < 0 || $c < 0)
		return;
	start_printing($s . '{',$o-1,$c);
	start_printing($s . '}',$o,$c-1);
}
printbraces(2);
?>

prints out

{{}}
{}{}