<?php

class Menu
{
    /**
     * @var string
     */
    private $_name;
    /**
     * @var Menu[]
     */
    private $_subMenus;

    function __construct($name)
    {
        $this->_name = $name;
        $this->_subMenus = [];
    }

    function addSubMenu($menu)
    {
        $this->_subMenus[] = $menu;
    }

    function removeSubMenu($menu)
    {
        foreach ($this->_subMenus as $index => $subMenu) {
            if ($subMenu == $menu)
                unset($this->_subMenus[$index]);
        }
    }

    function getSubMenus()
    {
        return $this->_subMenus;
    }

    function toString()
    {
        echo $this->_name . "\n";
    }
}

$root = new Menu(‘功能菜单‘);
$headMenu1 = new Menu(‘设置‘);
$headMenu2 = new Menu(‘管理‘);

$subMenu1 = new Menu(‘更新系统‘);
$subMenu2 = new Menu(‘关闭系统‘);
$subMenu3 = new Menu(‘用户系统‘);
$subMenu4 = new Menu(‘用户组系统‘);

$root->addSubMenu($headMenu1);
$root->addSubMenu($headMenu2);

$headMenu1->addSubMenu($subMenu1);
$headMenu1->addSubMenu($subMenu2);
$headMenu2->addSubMenu($subMenu3);
$headMenu2->addSubMenu($subMenu4);

$root->toString();
foreach ($root->getSubMenus() as $headMenu) {
    $headMenu->toString();
    foreach ($headMenu->getSubMenus() as $subMenu) {
        $subMenu->toString();
    }
}