【面霸2】

//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)

       class MyClass implements Iterator{

              private $vars = array();

              private $var1;

              private $var2;

              private $var3;

              function __set($name , $value){

                     $this->vars[$name] = $value;

              }

              function __get($name){

                     return $this->vars[$name];

              }

              public function rewind() {

                     reset($this->vars);

              }

              public function current() {

                     return current($this->vars);

              }      

              public function key() {

                     return key($this->vars);

              }      

              public function next() {

                     return next($this->vars);

              }

              public function valid() {

                     return $this->current() !== false;

              }

       }

 

       $it = new MyClass($values);

       $it->var1 = 1;

       $it->var2 = 2;

       $it->var3 = 3;

       foreach ($it as $a => $b) {

              print “$a: $b“;

       }

//2、用PHP实现一个双向队列

       class DoubleEndedQueue{

              protected $elements;

              public function __construct(){

                     $this->elements = array();

              }

              public function push($element){

                     array_unshift($this->elements , $element);

              }

              public function pop(){

                     return array_shift($this->element);

              }

              public function inject($element){

                     $this->elements[] = $element;

              }

              public function eject(){

                     array_pop($this->elements);

              }

       }

//3、请写一段PHP代码，确保多个进程同时写入同一个文件成功

       function write_file($filename, $content){

               $lock = $filename . ‘.lck‘;

               $write_length = 0;

               while(true) {

                     if( file_exists($lock) ) {

                            usleep(100);

                     } else {

                            touch($lock);

                            $write_length = file_put_contents($filename, $content, FILE_APPEND);

                            break;

                     }

               }

               if( file_exists($lock) ) {

                     unlink($lock);

               }

               return $write_length;

       }

//4、有一个一维数组，里面存储整形数据，请写一个函数，将他们按从大到小的顺序排列。要求执行效率高。并说明如何改善执行效率。

       function BubbleSort(&$arr){

              $cnt=count($arr);

              $flag=1;

              for($i=0;$i<$cnt;$i++)   {

                     if($flag==0){

                            return;

                     }

                     $flag=0;

                     for($j=0;$j<$cnt-$i-1;$j++){

                            if($arr[$j]>$arr[$j+1]){

                                   $tmp=$arr[$j];

                                   $arr[$j]=$arr[$j+1];

                                   $arr[$j+1]=$tmp;

                                   $flag=1;

                            }

                     }

              }

       }

       $test=array(1,3,6,8,2,7);

       BubbleSort($test);

       var_dump($test); 

//5、PHP获取远程web服务器时间的代码

       function get_time($server){

              $data = "HEAD / HTTP/1.1\r\n";

              $data .= "Host: $server\r\n";

              $data .= "Connection: Close\r\n\r\n";

              $fp = fsockopen($server, 80);

              fputs($fp, $data);

              $resp = ‘‘;

              while ($fp && !feof($fp))

                     $resp .= fread($fp, 1024);

              preg_match(‘/^Date: (.*)$/mi‘,$resp,$matches);

              return strtotime($matches[1]);

       }

       echo date(‘Y-m-d H:i:s‘,get_time("outofmemory.cn")); 

【面霸2】

原文：http://www.cnblogs.com/zhuyibo/p/3985172.html