php常见算法

1.使对象可以像数组一样进行foreach循环，要求属性必须是私有。(Iterator模式的PHP5实现，写一类实现Iterator接口)

<?php
    class Test implements Iterator{
    private $item = array('id'=>1,'name'=>'php');
 
    public function rewind(){
        reset($this->item);
    }
 
    public function current(){
        return current($this->item);
    }
 
    public function key(){
        return key($this->item);
    }
 
    public function next(){
        return next($this->item);
    }
 
    public function valid(){
        return($this->current()!==false);
    }
}
    //测试
    $t=new Test;
    foreach($t as $k=>$v){
        echo$k,'--->',$v,'<br/>';
    }
?>

 2.用PHP实现一个双向队列

<?php
    class Deque{
    private $queue=array();
    public function addFirst($item){
        return array_unshift($this->queue,$item);
    }
 
    public function addLast($item){
        return array_push($this->queue,$item);
    }
    public function removeFirst(){
        return array_shift($this->queue);
    }
 
    public function removeLast(){
        return array_pop($this->queue);
    }
}
?>