如何在递归树函数（PHP）中显示索引（＃行号）

Question

I would like to be able to print the index inside a recursive function and I don't really understand why it's not working... I'm able to print a table in the right order, but the counter is not working well ??? Every time it print a line, it should add one to the counter, but it's not really what's happening here... I'm a little confused over the recursion here. Any help would be greatly appreciated.

Here's the basic code example:

function outputMenu ($menu_tree, $cpt = 0) {
    $html = "";
    foreach ($menu_tree as $menu) {
        $cpt++;
        $html .= $cpt .'- '. $menu["name"]."<br>";
        if (count($menu['children']) > 0) {
            $html .= outputMenu ($menu["children"], $cpt);
        }               
    }
    return $html;
}
outputMenu($menu_tree);

And the results:

1- ablato
2- Malone
3- |--- the skulls 3
4- |--- Titanic
3- Uno test
4- |--- Alien Quadrilogie
5- |------ aliens are back
6- |------ Prison Break
7- |--------- 24 Hours
8- |------------ Marvels Agents of Shield
7- |------ the skulls
5- |--- Evasion
6- |--- star wars

Answer 1

Since it's a recursive function you will leave the foreach loop once you have children in your variable, sending the current index. Therefore you have values 3, 4 for the first children of number 2 and then you will once again continue the foreach with the value 3.

A simple solution would be using a variable outside your function.

Answer 2

Thanks, I have followed you lead using a global variable outside the function and I added

$menu_index = 0;

function outputMenu ($menu_tree) {
    global $menu_index;
    $html = "";
    foreach ($menu_tree as $menu) {
        $menu_index++;
        $html .= $menu_index .'- '. $menu["name"]."<br>";
        if (count($menu['children']) > 0) {
            $html .= outputMenu ($menu["children"]);
        }               
    }
    return $html;
}
outputMenu($menu_tree);

at the beginning of my function and it's now working perfectly. Big thanks :)