php产生随机数的两种方法实例代码 输出随机IP

本人是asp程序员，这是首次写php程序，一点心得发上来共享
复制代码 代码如下:

<?php
$ip2id= round(rand(600000, 2550000) / 10000); //第一种方法，直接生成
$ip3id= round(rand(600000, 2550000) / 10000);
$ip4id= round(rand(600000, 2550000) / 10000);
//下面是第二种方法，在以下数据中随机抽取
$arr_1 = array("218","218","66","66","218","218","60","60","202","204","66","66","66","59","61","60","222","221","66","59","60","60","66","218","218","62","63","64","66","66","122","211");
$randarr= mt_rand(0,count($arr_1)-1);
$ip1id = $arr_1[$randarr];
echo $ip1id;
echo ".";
echo $ip2id;
echo ".";
echo $ip3id;
echo ".";
echo $ip4id;
?>

例输出结果为 218.28.131.182
这个程序的特点是,生成的ip第一个字段时在指定范围内的，设定的几个是国内常见号段，也就是说生成的ip地址大部分是国内的
核心代码:
复制代码 代码如下:
<?php
$arr_1 = array("http://66.249.89.99","http://66.249.89.104","http://74.125.71.105");
$randarr= mt_rand(0,count($arr_1)-1);
$gip= $arr_1[$randarr];
echo $gip."$randarr";
?>