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Find out which random number generator was seeded in C ++

I have an unmanaged C ++ console application in which I use srand () and rand (). I don't need this to solve a specific problem, but it was curious: the original seed is passed to srand () somewhere in the memory, which can I request? Is there any way to find out what a seed is?

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4 answers

The seed does not need to be stored; only the last random number is returned.

Here is an example from manpage:

       static unsigned long next = 1;

       /* RAND_MAX assumed to be 32767 */
       int myrand(void) {
           next = next * 1103515245 + 12345;
           return((unsigned)(next/65536) % 32768);
       }

       void mysrand(unsigned seed) {
           next = seed;
       }
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If you have a simple linear congruent generator for which you have several values, this gives a system of equations:

 v1 = ( seed * a + b ) % m
 v2 = (   v1 * a + b ) % m;
 v3 = (   v2 * a + b ) % m;
...

, :

seed = (v1 - b)/a (mod m)

, mod m ( , (0 < seed < m) ). v1 - b , m, .

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