PHP round() 函数四舍五入php函数

PHP round() 函数四舍五入php函数 在php中round() 函数的使用是对浮点数进行四舍五入。 round(x,prec)

 x,是要处理的浮点型数据
 prec,保存几位小数
提示和注释
注释：PHP 默认不能正确处理类似 "12,300.2" 的字符串。

注释：prec 参数是在 PHP 4 中被引入的。。

*/

//实例浮点数的截断函数，返回值仍为浮点数。

  
  $foo   =   round(3.4);     //   $foo   ==   3.0  
  $foo   =   round(3.5);     //   $foo   ==   4.0  
  $foo   =   round(3.6);     //   $foo   ==   4.0  
  $foo   =   round(3.6,   0);     //   equivalent   with   above  
   
  $foo   =   round(1.95583,   2);     //   $foo   ==   1.96  
   
  $foo   =   round(1241757,   -3);     //   $foo   ==   1242000 
 
//round实例二

echo(round(0.68));
echo(round(0.40));
echo(round(0.3));
echo(round(-3.30));
echo(round(-4.90));

/*

1
0
0
-3
-5
*/
//返回将 x 根据指定精度 prec （十进制小数点后数字的数目）进行四舍五入的结果。prec 也可以是负数或零（默认值

  if($_POST[submit]){
    $username= str_replace(" ","",$_POST[username]);
    $sql="select * from user_list where `username` = '$username'";
    $query=mysql教程_query($sql);
    $us=is_array($row=mysql_fetch_array($query));
    $ps教程= $us ? md5($_POST[password].ALL_PS)== $row[password] : FALSE;
    $pw=$ps?$_SESSION["code"]==$_POST[code]:FALSE;

    if($ps){
     $_SESSION[uid]=$row[uid];
     $_SESSION[user_shell]=md5($row[username].$row[password].ALL_PS);
        $_SESSION[times]=mktime();

        if($pw){
     echo "登陆成功";
     }
     else{
      echo "验证码错误";
      session_destroy();
     }
    }else{

        echo "密码或者用户名错误";
         session_destroy();
    }

  }

 

?>

  <form action="" method="post">

  用户名：<input type="text" name="username" style="height:23px" /><br>
  密　码：<input type="password" name="password"  style="height:23px" /><br>
  验证码：<input type="code" name="code" size="10" style="height:23px" />
  <img src="imgcode.php">
  <br><br>
  <input type="submit" name="submit" value="登陆"/>
  </form>
 
  数据库教程结构
  --
-- 表的结构 `user_list`
--

CREATE TABLE `user_list` (
  `uid` int(11) NOT NULL auto_increment,
  `m_id` varchar(5) NOT NULL,
  `username` varchar(25) NOT NULL,
  `password` varchar(64) NOT NULL,
  PRIMARY KEY  (`uid`)
) ENGINE=MyISAM  DEFAULT CHARSET=gb2312 AUTO_INCREMENT=11 ;

--
-- 导出表中的数据 `user_list`
--

INSERT INTO `user_list` (`uid`, `m_id`, `username`, `password`) VALUES
(9, '1', 'admin', '75cf565ad38d0f837c43363e402b1a00'),
(10, '2', 'admin2', '75cf565ad38d0f837c43363e402b1a00');
 

<?php教程
$arr=array(
                 0=>array('title' => '新闻1', 'viewnum' => 123, 'content' => 'ZAQXSWedcrfv'),
                 1=>array('title' => '新闻2', 'viewnum' => 99, 'content' => 'QWERTYUIOPZXCVBNM')
                );
?>
如果你想统计数组$arr的长度，也就是说该二维数组只有两条新闻，你想要的数字也是2，但是如果使用count($arr)不同版本的php，统计的结果是不一样的；
后来在php手册中发现，count函数还有第二个参数，解释如下：
count函数有两个参数：
0(或COUNT_NORMAL)为默认,不检测多维数组(数组中的数组);
1(或COUNT_RECURSIVE)为检测多维数组，
所以如果要判断读取的数组$arr是不是有新闻信息，就要这样写了：
<?php
if(is_array($arr) && count($arr,COUNT_NORMAL)>0 )
{
  .....
} else {
  .....
}
?>
你可以使用这样的代码来测试该函数：
<?php
$arr=array(
                 0=>array('title' => '新闻1', 'viewnum' => 123, 'content' => 'ZAQXSWedcrfv'),
                 1=>array('title' => '新闻2', 'viewnum' => 99, 'content' => 'QWERTYUIOPZXCVBNM')
               );
echo '不统计多维数组：'.count($arr,0);//count($arr,COUNT_NORMAL)
echo "<br/>";
echo '统计多维数组：'.count($arr,1);//count($arr,COUNT_RECURSIVE)
?>
好了，到此为止，已经解决php中获取二维或多维数组的第一维长度的问题！

方法一
<?php教程
echo strtotime('last Monday');
echo '<br />';
echo strtotime('next Sunday');
?>

方法二
<? 

02 function getMonSun(){ 

03     $curTime=time(); 

04         

05     $curWeekday = date('w'); 

06   

07      //为0是 就是 星期七 

08     $curWeekday = $curWeekday?$curWeekday:7; 

09   

10   

11     $curMon = $curTime - ($curWeekday-1)*86400; 

12     $curSun = $curTime + (7 - $curWeekday)*86400; 

13        

14     $cur['Mon'] = $curMon; 

15     $cur['Sun'] = $curSun; 

16   

17     return $cur; 

18 } 

19     $cur = getMonSun(); 

20   

21     echo date('Y-m-d',$cur['Mon']); 

22     echo "rn"; 

23     echo date('Y-m-d',$cur['Sun']); 

24 ?>

方法三

<? 

02 function getMonSun(){ 

03      $curTime=time(); 

04         

05      //求出当前是星期几： 

06      $curWeekday = date('w'); 

07         

08      //如果是周一则减上7*86400周二减上6*86400，依此类推得到周一的时间戳： 

09      switch ($curWeekday) { 

10      case 0: 

11      $curMon = $curTime-7*86400; 

12          $curSun = $curTime; 

13      break; 

14      case 1: 

15      $curMon = $curTime; 

16           $curSun = $curTime+6*86400; 

17      break; 

18      case 2: 

19      $curMon = $curTime-1*86400; 

20          $curSun = $curTime+5*86400; 

21      break; 

22      case 3: 

23      $curMon = $curTime-2*86400; 

24          $curSun = $curTime+4*86400; 

25      break; 

26      case 4: 

27      $curMon = $curTime-3*86400; 

28          $curSun = $curTime+3*86400; 

29      break; 

30      case 5: 

31      $curMon = $curTime-4*86400; 

32          $curSun = $curTime+2*86400; 

33      break; 

34      case 6: 

35      $curMon = $curTime-5*86400; 

36          $curSun = $curTime+1*86400; 

37      break; 

38     } 

39     $cur['Mon'] = $curMon; 

40     $cur['Sun'] = $curSun; 

41   

42     return $cur; 

43 } 

44 $cur = getMonSun(); 

45          echo date('Y-m-d',$cur['Mon']); 

46          echo "rn"; 

47      echo date('Y-m-d',$cur['Sun']); 

48 ?>

 

try{
    $tor = new TorHttp('127.0.0.1', 9050);
    $data = array('username' => 'liujun');
    $headers = array('Cookie' => 'php教程id=123456; xx=v');
    echo $tor->get('http://host.com/testsocks.php', $headers);
    $tor->newId('123456');
}catch(Exception $e){
    if($e->getCode() == 9999){
        $tor->newId('123456');
    }
    echo $e->getMessage() . "n";
}
*/

class Tool_TorHttp
{
    /**
     * Tor提供的socks服务器
     *
     * @var <string
     */
    private $_host;

    /**
     * socks服务的连接
     *
     * @var <stream>
     */
    private $_sock;

    /**
     * 构造函数
     *
     * @param <string> $host socks服务器地址
     * @param <int> $port
     */
    public function __construct($host = '127.0.0.1', $port = 9050)
    {
        $this->_host = $host;
        @ $this->_sock = fsockopen($host, $port, $errorCode, $error, 5);

        if($errorCode){
           throw new Exception('不能连接代理服务器');
        }

        //建立应用层的连接
        fwrite($this->_sock, pack('C3', 5, 1, 0));
        $resp = fread($this->_sock, 1024);
        $resp = unpack('Cversion/Cmethod', $resp);
        if($resp['version'] != 5 || $resp['method'] != 0){
            $this->_sock = null;
            throw new Exception('代理服务器不可用或者需要连接密码');
        }
    }

    /**
     * 连接目标主机
     *
     * @param <type> $host
     * @param <type> $port
     */
    private function _connect($host, $port)
    {
        //ip和域名描述的服务器用不同的报文格式
        $lip = ip2long($host);
        if(empty($lip)){
            $pack = pack('C5', 5, 1, 0, 3, strlen($host)) . $host . pack('n', intval($port));
        }else{
            $pack = pack('C4Nn', 5, 1, 0, 1, $lip, $port);
        }
        fwrite($this->_sock, $pack);
        $resp = '';
        $counter = 0;
        while(true){
            if(feof($this->_sock)){
                break;
            }
            $resp .= fread($this->_sock, 1024);
            if(!empty($resp) || $counter == 50){
                break;
            }
            $counter += 1;
        }

        $resp = unpack('Cversion/Crep', $resp);
        if(($resp['version'] != 5) || ($resp['rep'] != 0)){
            throw new Exception("请求的服务[$host:$port]暂时不可用，或者Tor不能到达，如果反复发生，请尝试重启Tor", 9999);
        }
    }

    /**
     * 发起一次http的get请求
     *
     * @param <type> $url
     * @return <string>
     */
    public function get($url, $headers = array())
    {
        $ua = parse_url($url);
        if(empty($ua['port'])){
            $ua['port'] = 80;
        }

        $this->_connect($ua['host'], $ua['port']);

        $requestUri = $ua['path'];

        if(!empty($ua['query'])){
                $requestUri .= '?' . $ua['query'];
        }

        $headers['Host'] = $ua['host'];
        if(!isset($headers['User-Agent'])){
            $headers['User-Agent'] = "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10 GTB5";
        }
        $headers['Connection'] = 'close';

        fwrite($this->_sock, "GET {$requestUri} HTTP/1.1n");
        foreach ($headers as $key => $val){
            fwrite($this->_sock, "{$key}: {$val}n");
        }
        fwrite($this->_sock, "n");

        $resp = '';
        while(!feof($this->_sock)){
            $resp .= fread($this->_sock, 1024);
        }
        return $resp;
    }

    /**
     * 发起一次http的post请求
     *
     * @param <type> $url
     * @param <type> $data
     * @param <type> $headers
     * @return <type>
     */
    public function post($url, $data, $headers = array())
    {
        $ua = parse_url($url);

        if(empty($ua['port'])){
            $ua['port'] = 80;
        }

        $this->_connect($ua['host'], $ua['port']);

        if(isset($ua['path']) && !empty($ua['path'])){
            $requestUri = $ua['path'];
        }else{
            $requestUri = '/';
        }

        if(!empty($ua['query'])){
            $requestUri .= '?' . $ua['query'];
        }

        if(!isset($headers['User-Agent'])){
            $headers['User-Agent'] = "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10 GTB5";
        }
        $headers['Connection'] = 'close';

        $data = $this->_parseData($data);

        fwrite($this->_sock, "POST {$requestUri} HTTP/1.1n");
        fwrite($this->_sock, "Host: {$ua['host']}n");
        fwrite($this->_sock, "Content-Type: application/x-www-form-urlencodedn");
        fwrite($this->_sock, "Content-Length: " . strlen($data) . "n");
        foreach ($headers as $key => $val){
            fwrite($this->_sock, "{$key}: {$val}n");
        }
        fwrite($this->_sock, "n");
        fwrite($this->_sock, $data . "n");

        $resp = '';
        while(!feof($this->_sock)){
            $resp .= fread($this->_sock, 1024);
        }
        return $resp;
    }

    /**
     * 更新Tor的身份
     *
     * @param <type> $password
     * @param <type> $port
     * @return <type>
     */
    public function newId($password = '', $port = 9051)
    {
        if(!empty($password) && $password[0] != '"'){
            $password = '"' . $password . '"';
        }

        //创建到tor控终端的连接
        @ $sock = fsockopen($this->_host, $port, $errorCode, $error, 5);
        if($errorCode){
           throw new Exception('不能连接代理服务器控制端，请检查端口号');
        }

        fwrite($sock, "AUTHENTICATE {$password}n");
        $resp = fread($sock, 1024);
        if(!preg_match('/^250/', $resp)){
            throw new Exception('Tor控制认证失败，请确认密码正确');
        }

        fwrite($sock, "SIGNAL NEWNYMn");
        $resp = fread($sock, 1024);
        if(!preg_match('/^250/', $resp)){
            throw new Exception('更新身份失败，请重试');
        }
        return true;
    }

    private function _parseData($data)
    {
        if(empty($data) || !is_array($data)){
                return $data;
        }
        $encoded = '';
        while (list($k, $v) = each($data)) {
            $encoded .= $k . "=" . $v . '&';
        }
        return substr($encoded, 0, -1);
    }

    public function  __destruct()
    {
        fclose($this->_sock);
        $this->_sock = null;
    }
}