php随机数rand跟mt_rand
php随机数rand和mt_rand
今天想写个扔骰子并统计点数概率的小程序，使用如下方法生成随机数
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mt_rand() 使用 Mersenne Twister 算法返回随机整数，mt_rand()是rand()的一个非正式的替代品。
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说明
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如果没有提供可选参数 min 和 max，mt_rand() 返回 0 到 RAND_MAX 之间的伪随机数。例如想要 5 到 15（包括 5 和 15）之间的随机数，用 mt_rand(5, 15)。
很多老的 libc 的随机数发生器具有一些不确定和未知的特性而且很慢。PHP 的 rand() 函数默认使用 libc 随机数发生器。mt_rand() 函数是非正式用来替换它的。该函数用了 Mersenne Twister 中已知的特性作为随机数发生器，它可以产生随机数值的平均速度比 libc 提供的 rand() 快四倍。
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