How can recursion be used to build and display a tree structure in PHP?

To build and display a tree structure using recursion in PHP, you can create a recursive function that traverses the tree nodes and prints them out in a hierarchical manner. Each node can have child nodes, which are also printed out recursively. This approach allows you to dynamically build and display tree structures of varying depths. 

class Node {
    public $value;
    public $children = [];

    public function __construct($value) {
        $this->value = $value;
    }

    public function addChild(Node $node) {
        $this->children[] = $node;
    }
}

function displayTree(Node $node, $level = 0) {
    echo str_repeat("-", $level) . $node->value . "\n";

    foreach ($node->children as $child) {
        displayTree($child, $level + 1);
    }
}

// Build a tree structure
$root = new Node("Root");
$child1 = new Node("Child 1");
$child2 = new Node("Child 2");
$child3 = new Node("Child 3");

$root->addChild($child1);
$root->addChild($child2);
$child2->addChild($child3);

// Display the tree structure
displayTree($root);

Keywords

recursion tree structure PHP display build

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