Random Number...

[Sylus101]

I've found (though I wouldn't be adverse to getting another suggestion) about the proper way to generate a random number (with a max value), but to seed the random number generator I'd like to use the current DS Clock time. I can't seem to find any macro or define for it... what am I missing?

[WinterMute]

Code: Select all

#include <nds.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(int argc, char **argv) {
  consoleDemoInit();
  srand(time(NULL));
  printf("random number is %d\n", rand());
  while(1) swiWaitForVBlank();
}

[Sylus101]

Thanks, that works, lol.

Another quick question... should you only have to call srand() once? What I mean is, afterwards will rand() generate a number seeded by the time at that moment or at the moment srand() was called.

[vuurrobin]

time is just a function that a number. so srand will always use the time it was given when you called time().
however, you only have to call srand() once. when you call rand(), it will change the seed for you, so calling rand() twice should give you 2 different numbers.

[Jell]

I ran through this problem lately, actually srand(time(NULL)) did not randomize my rand() calls.

My guess WAS that the function time() returns a pointer, therefore your seed will always be the same (making the whole process useless).

[Edit:] But obviously I was guessing wrong!

[WinterMute]

Actually, srand(time(NULL)) will work fine, just not on most emulators.

[Jell]

Oups that's true! Sorry for the wrong advice...