<?php
	$recv_text = $_GET['text'];
	$len = strlen($recv_text);
	$ret = "";
	for( $i = 0; $i < $len; $i++){
		$cha = substr($recv_text, $i, 1);
		$ascii_code = ord($cha);
		if ( $ascii_code  >= ord('a') && $ascii_code <= ord('z') ) {
			$cha2 = chr($ascii_code - 32);
		} elseif ( $ascii_code  >= ord('A') && $ascii_code <= ord('Z') ) {
			$cha2 = chr($ascii_code + 32);
		} else {
			$cha2 = $cha;
		}
		$ret  = $ret . $cha2;
	}
	echo "Input is [$recv_text]　　Output is [$ret].";
?>