遍历

先序遍历 中序遍历 后序遍历

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<?php

class Node{
    public  $l_child;
    public $r_child;
    public $var ;

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


function preTraverse(Node $root){
    echo $root->val."<br/>";
    if($root->l_child != null) preTraverse($root->l_child);
    if($root->r_child != null ) preTraverse($root->r_child);
}

function inTraverse(Node $root){
    if($root->l_child != null) inTraverse($root->l_child);
    echo $root->val."<br/>";
    if($root->r_child != null ) inTraverse($root->r_child);
}

function postTraverse(Node $root){
    if($root->l_child != null) postTraverse($root->l_child);
    if($root->r_child != null ) postTraverse($root->r_child);
    echo $root->val."<br/>";
}


$node1 = new Node(1);
$node2 = new Node(2);
$node3 = new Node(3);
$node4 = new Node(4);
$node5 = new Node(5);
$node6 = new Node(6);
$node7 = new Node(7);
$node8 = new Node(8);

$node1->l_child=($node2);
$node1->r_child=($node3);
$node2->l_child=($node4);
$node2->r_child=($node5);
$node3->l_child=($node6);
$node4->l_child=($node7);
$node4->r_child=($node8);

postTraverse($node1);

遍历文件 

---

header("Content-Type:text/html;charset=utf-8");

function ls_dir($dir){
    if(substr($dir, -1) != "/"){
        $dir = $dir."/";
    }

    if(!is_dir($dir))return;
    /*处理 返回当前目录的文件目录*/

    if(!is_readable($dir)){
        echo "没有打开权限!   ",$dir,"<br/>";
        return;
    }
    $list = opendir($dir);


    while($file = readdir($list)){
        if($file == "." or $file=="..") continue;
        echo $dir.$file,"<br/>";
        ls_dir($dir.$file);
    }
}



ls_dir("/var/lib/mysql");