In the previous article, we introduced to you three implementation methods of recursive algorithms, namely "static variables", "global variables" and "passing parameters by reference". Friends who need it can learn about "PHP Recursive Algorithm (1)" "PHP Recursive Algorithm (2)" "PHP Recursive Algorithm (3)"

Now we will introduce to you how to debug and run the recursive algorithm of PHP reference parameter passing through xdebug.

The code is as follows:

<?php
function test($a=0,&$result=array()){
    $a++;
    if ($a<5){
        $result[]=$a;
        test($a,$result);
    }
    echo $a."<hr>";
    return $result;
}
var_dump(test());

First create a breakpoint in the first line of the test method body.

#Then click the down arrow to start debugging the "Run" program.

The first judgment cycle is as follows:

The last judgment cycle As follows:

The final output is as follows:

How to configure xdebug in PHPStorm Tools and use》

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