php面试编程题汇总

<?php/*MYSQL数据库优化建议：1.选择合适的字段2.使用连接查询代替子查询3.使用union代替临时表4.建立索引5.建立事务6.用锁定表优化事务7.用外键优化锁定表8.优化查询语句*///翻转字符串function Strrev_one($string){$str=$string=''?'':$string;$num=strlen($str);$str_end='';for($i=$num-1;$i>=0;$i--){$str_end.=$str[$i];}return $str_end;}//实现中文字符截取无乱码function GBstr($string,$start,$lenght){if(strlen($string)>$lenght){$len=$start+$lenght;$str_end='';for($i=0;$i<$len;$i++){if(ord(substr($string,$i,1))>0xa0){$str_end.=substr($string,$i,2);$i++;}else{$str_end.=substr($string,$i,1);}}return $str_end;}else{return $string;}}//打印客户端和服务端ip地址/*IP:echo $_SERVER['REMOTE_ADDR']; 或者: getenv('REMOTE_ADDR');打印服务器IP:echo gethostbyname("")*///准确获得服务端ip地址function getip(){if (getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown')){ $ip = getenv('HTTP_CLIENT_IP');}else if (getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')){$ip = getenv('HTTP_X_FORWARDED_FOR');}else if (getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')){ $ip = getenv('REMOTE_ADDR');}else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')){$ip = $_SERVER['REMOTE_ADDR'];}preg_match("/[\d\.]{7,15}/", $ip, $temp);$ip = $temp[0] ? $temp[0] : 'unknown';unset($temp);return $ip;}//修改session生存时间setcookie(session_name(),session_id(),$lifetime);session_set_cookie_params($lifetime);//获取网址首页的全部内容如function GetConect($address){$judge=preg_match("/^http:\/\/[A-Za-z0-9]+\.[A-Za-z0-9]+[\/=\?%\-&_~`@[\]\':+!]*([^<>\"]) *$/",$address)?true:false;if($judge){$readcontents=fopen($address, "rb");$contents = stream_get_contents($readcontents);fclose($readcontents);return $contents;}return file_get_contents($address);}//php中的heredoc特殊字符串/*heredoc的语法是用"<<<"加上自己定义成对的标签，在标签范围內的文字视为一个字符串例子:$STR=<<<EOTMY NAME IS HELLO WORLD!EOT;*///验证电子邮箱的函数function checkEmail($email){$pregEmail="/([a-z0-9]*[-_\.]?[a-z0-9]+)*@([a-z0-9]*[-_]?[a-z0-9]+)+[\.][a-z]{2,3}([\.][a-z]{2}) ?/i";return preg_match($pregEmail,$email);}//获得当前脚本执行路径和参数/*$script_name = basename(__file__); print_r($script_name);*///排序<!--冒泡法-->function maopao($array){if(count($array)<=1) return $a;$a=$array;$num=count($a);$i='';$j='';for ($i=1;$i<$num;$i++){for($j=$num-1;$j>=$i;$j--){if($a[$j]>$a[$j-1]){$temp=$a[$j];$a[$j]=$a[$j-1];$a[$j-1]=$temp;}}}return $a;}//从一个标准的url里面取出扩展名function getExt($url){$arr = parse_url($url);//标准化url$file = basename($arr['path']); //取得url的path部分$ext = explode(".",$file); //裁剪return $ext[1];}//修改标准的html里面的meter头Function HTMLchange($html){$pattern = "/<meta\s+http-equiv=(\'|\")?Content-Type(\'|\")?\s+content=(\'|\")text\/html;\s+charset=(.*)(\ '|\")>/i";$replacement = "<meta http-equiv='Content-Type' content='text/html; charset=big5'>";$result = preg_replace($pattern,$replacement, $html);echo htmlspecialchars($result);}//函数计算二个文件的相对路径$a相对于$b的路径function getRelativePath($a, $b) {$returnPath = array(dirname($b));$arrA = explode('/', $a);$arrB = explode('/', $returnPath[0]);for ($n = 1, $len = count($arrB); $n < $len; $n++) {if ($arrA[$n] != $arrB[$n]) {break;}}if ($len - $n > 0) {$returnPath = array_merge($returnPath, array_fill(1, $len - $n, '..'));}$returnPath = array_merge($returnPath, array_slice($arrA, $n));return implode('/', $returnPath);}//遍历文件夹下的所有子文件夹和文件function listDir($dir = '.'){if ($handle = opendir($dir)) {while (false !== ($file = readdir($handle))) {if($file == '.' || $file == '..'){continue;}if(is_dir($sub_dir = realpath($dir.'/'.$file))){echo 'FILE in PATH:'.$dir.':'.$file.'<br>';listDir($sub_dir);}else{echo 'FILE:'.$file.'<br>';}}closedir($handle);}}//猴子选大王$n是猴子的总数,$m是踢出的位置function MonkeyKing($n,$m){//构造数组for($i=1 ;$i<$m+1 ;$i++){$arr[] = $i ;}$i = 0 ; //设置数组指针while(count($arr)>1){//遍历数组，判断当前猴子是否为出局序号，如果是则出局，否则放到数组最后if(($i+1)%$n ==0) {unset($arr[$i]) ;} else {array_push($arr ,$arr[$i]) ; //本轮非出局猴子放数组尾部unset($arr[$i]) ; //删除}$i++ ;}return $arr ;}/*** 有m只猴子，从1开始数到n，第n只猴子退出，如此循环执行下去，直到剩下最后一只猴子，求该猴子的编号？** 递归算法* @param int $m 猴子数* @param int $n 出局数* @param int $current 指针*/ function killMonkey($monkeys , $n , $current = 0){$num = 1;if(count($monkeys) == 1){echo $monkeys[0]."成为猴王了";return;}else{for($num;$num<$n;$num++){if($current==$n){$current=0;break;}$current++;}//echo $monkeys[$current]."的猴子被踢掉了<br/>";array_splice($monkeys , $current , 1);//var_dump($monkeys);killMonkey($monkeys , $n , $current);}}function KingMonkey（$m,$n）{for($i=1 ;$i<$m+1 ;$i++){$monkeys [] = $i ;}killMonkey($monkeys , $n );}//多进程/线程同时读写一个文件的问题function same_time_write($address1){//写入$fp = fopen($address, 'ab'); //从后面flock($fp, LOCK_EX); //先锁住文件，等待fwrite($fp, 'Just A Test String.......'); //开始写入flock($fp, LOCK_UN); //释放锁fclose($fp); //关闭读操作//读取$fp = fopen($address, 'r');flock($fp, LOCK_SH);//从文件读取flock($fp, LOCK_UN);fclose($fp);}//打开function T_put($filename,$string){$fp = fopen($filename,'a'); //追加方式打开if (flock($fp, LOCK_EX)){ //加写锁fputs($fp,$string); //写文件flock($fp, LOCK_UN); //解锁}fclose($fp);}//取文件function T_get($filename,$length){$fp = fopen($filename,'r'); //追加方式打开if (flock($fp, LOCK_SH)){ //加读锁$result = fgets($fp,$length); //读取文件flock($fp, LOCK_UN); //解锁}fclose($fp);return $result;}//写入function add_num( $file_path , $messageid , $num){$file_path_user = $file_path . '/' . $messageid;//把路径加上被投人ID，去往被投人的文件夹while(file_exists($file_path_user . '/NO_WRITABLE')){//为防止并发写入文件错误，判断一个文件是否存在，若存在证明正在插入，进入死循环，否则直接插入touch($file_path_user . '/NO_WRITABLE');//新建验证文件file_put_contents( $file_path_user.'/num.txt',intval(file_get_contents($file_path_user.'/num.txt')) + $num); //增加票数unlink($file_path_user. '/NO_WRITABLE');//删除验证文件}}//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);}}//php递归function test($n) {echo $n." ";if($n>0)test($n-1);//递归elseecho "<-->";echo $n." ";}?>。