使用从奇数流中取模来生成“随机”数

Question

i want to generate a pseudo-random bool stream based on a modulo operation on another stream of integers (say X), so the operation would be

return ( X % 2);

The only problem is that X is a stream of integers that always ends in 1, so for instance would be somehing like 1211, 1221, 1231, 1241 .... is there a way for me to disregard the last bit (without using string manip) so the test doesnt always pass or always fail?

Answer 1

那么(X / 10) % 2呢？

Answer 2

If you'd otherwise be happy to use the last bits, use the penultimate bits instead:

return (x & 0x2) >> 1;

So say the next number from your stream is 23:

  1 0 1 1 1  // 23 in binary
& 0 0 0 1 0  // 0x2 in binary
-----------
  0 0 0 1 0

Shifting that right by one bit ( >> 1 ) gives 1. With 25, the answer would be 0:

  1 1 0 0 1
& 0 0 0 1 0
-----------
  0 0 0 0 0

Answer 3

return ( x%20/10 );