recursive binary search

I'm attempting to code a recursive binary search, but am having trouble. It's possible that I'm doing something fundamentally wrong here with passing parameters to a recursive function. More likely, there's something simple that I'll kick myself for posting, but darned if I can see the problem. // Start by initializing an my array of associative arrays. $i=0; for ($date = 20000801; $date <= 20000815; $date++) { $myarray[$i] = array ( "date" => $date, "index" => $i ); $i++; } // Search $array for $finddate. $low is first element (0) and // $high is last element (count($array) - 1). function bin_search( &$array, $low, $high, $finddate ) { echo "\$low = " . $low . "<BR>"; echo "\$high = " . $high . "<BR>"; echo "\$finddate = " . $finddate . "<BR>"; echo "\$array[1][\"date\"] = " . $array[1]["date"] . "<BR>"; if ($low > $high) { return -1; // no match } $mid = floor((high + low)/2); if ($array[$mid]["date"] = $finddate) { // match return $mid; } else if ($array[$mid]["date"] > $finddate) { bin_search($array, $low, $mid-1, $finddate); } else if ($array[$mid]["date"] < $finddate) { bin_search($array, $mid+1, $high, $finddate); } else { return -1; } } // Call the function and echo output $myvar = bin_search ($myarray, 0, count($myarray)-1, 20000802); echo "<P>The function returned $myvar"; The function is called only once (doesn't recurse), as evidenced by the output: $low = 0 $high = 14 $finddate = 20000802 $array[1]["date"] = 20000802 The function returned 0