Recursive count of children in nested arrays + changing values by reference - php

Question

I know this is basic recursion but I get stuck anyway :(
I need to count how many elements each element has below it (children, grandchildren,...) and write that value into original array.
My example array:
$table = [
1 => [
'id' => 1,
'children_count' => 0
],
2 => [
'id' => 2,
'children_count' => 0,
'children' => [
3 => [
'id' => 3,
'children_count' => 0,
'children' => [
4 => [
'id' => 4,
'children_count' => 0,
'children' => [
5 => [
'id' => 5,
'children_count' => 0
],
6 => [
'id' => 6,
'children_count' => 0
]
]
]
]
]
]
]
];
My recursion code:
function count_children(&$array){
foreach($array['children'] as &$child){
if(isset($child['children'])){
$array['children_count'] += count_children($child);
}
else return 1;
}
}
Call for recursion:
//call for each root element
foreach($table as &$element){
if(isset($element['children'])) count_children($element);
}
Expected output:
$table = [
1 => [
'id' => 1,
'children_count' => 0
],
2 => [
'id' => 2,
'children_count' => 4,
'children' => [
3 => [
'id' => 3,
'children_count' => 3,
'children' => [
4 => [
'id' => 4,
'children_count' => 2,
'children' => [
5 => [
'id' => 5,
'children_count' => 0
],
6 => [
'id' => 6,
'children_count' => 0
]
]
]
]
]
]
]
];
Where did I got it wrong?
My function does something, element 3 gets value 1, but thats about it.
Here is the ideone link: http://ideone.com/LOnl3G

Answer 1

function count_children(&$table){
$count1 = 0;
foreach($table as &$array) {
$count = 0;
if (isset($array['children'])) {
$count += count($array['children']);
$count += count_children($array['children']);
}
$array['children_count'] = $count;
$count1 += $count;
}
return $count1;
}
count_children($table);
print_r($table);