谢谢

谢了。我们还是能够控制这种随机。只是每个种子产生的随机数，内部是如何随机得来的，怎么会一样，是一条规则么？

谢了，受用

Random-number functions and CALL routines generate streams of pseudo-random numbers from an initial starting point, called a seed, that either the user or the computer clock supplies. A seed must be a nonnegative integer with a value less than 231-1 (or 2,147,483,647). If you use a positive seed, you can always replicate the stream of random numbers by using the same DATA step. If you use zero as the seed, the computer clock initializes the stream, and the stream of random numbers cannot be replicated.

谢谢楼上各位大大的解答。很有用！