php--常见算法1

<?php
//递归输出123321
function digui($num){
echo $num;
if($num<3){
digui($num+1);
}
echo $num;
}
digui(1);


//递归输出1+2+3+4+5+...=
function leijia($num){
if($num>1){
$num+=leijia($num-1);

}
return $num;
}
$res=leijia(5);
echo $res;

?>