php函数的返回值

<?php
function she($a, $b, $c) {
    return array(
        $c,
        $b,
        $a
    );
}
list($x, $y, $z) = she(2, 3, 4);
echo '$x=' . $x . '$y=' . $y . '$z=' . $z;
?>

<?php
function add($shu) {
    return $shu + 1;
}
echo add(2) . ' 
';
function she($a, $b, $c) {
    return array(
        $c,
        $b,
        $a
    );
}
list($x, $y, $z) = she(2, 3, 4);
echo '$x=' . $x . ' 
$y=' . $y . ' 
$z=' . $z;
?>

<?php
function results($string) {
    $result = array();
    $result[] = $string; //原字符串
    $result[] = strtoupper($string); //全部换成大写
    $result[] = strtolower($string); //全部换成小写
    $result[] = ucwords($string); //单词的首字母换成大写
    return $result;
}
$multi_result = results('The quick brown fox jump over the lazy dog');
print_r($multi_result);
?>

Array  
(  
[0] => The quick brown fox jump over the lazy dog  
[1] => THE QUICK BROWN FOX JUMP OVER THE LAZY DOG  
[2] => the quick brown fox jump over the lazy dog  
[3] => The Quick Brown Fox Jump Over The Lazy Dog  
)

<?php
function test(&$a, &$b) {
    $a = 1000;
    $b = 12000;
    return $a + $b;
}
$a = 10;
$b = 12;
$c = test($a, $b); //注意这里没有 & 了.
//显示修改后的值
echo $a;
echo $b;
echo $c; //这是函数返回值；
?>