编辑代码

<?php 
function arithmetic($funName,$m,$n){
    //return $funName($m,$n);
    //return call_user_func($funName,$m,$n);
    return call_user_func_array($funName,array($m,$n));
}
function add($m,$n){
    return $m+$n;
}
$sum=arithmetic('add',5,3);
echo '5+3='.$sum;
?>