Random-nunmber

代码说明：

  程序生成的随机数,真正的名字叫做“伪随机数”,需要有一个种子来初始化 使用当前时间去初始化种子,就能得到不同的伪随机数序列(Program generates random numbers, the real name is " pseudo-random number," the need for a seed to initialize the current time to initialize the seed, you can get different pseudo-random number sequence)