PHP面试题 foreach($arr as ＆$value)与foreach($arr as $value)的用法

面试题：

<?php
$arr = [0,1,2,3,4];

foreach ($arr as &$val) {
    
	// nothing
}
foreach ($arr as $val) {
    
	// nothing
}
// 会输出什么
var_export($arr);
/********* ** 答案：** *********/
array (
  0 => 1,
  1 => 2,
  2 => 3,
  3 => 8,
  4 => 'a',
  5 => 'a',
)

详细解释可参考：
https://blog.csdn.net/smxdgf/article/details/105370166