Homebrew I need help with rand()

[randomdev]

Hi, I'm using the rand() function to determine random x and y positions (I'm working on a project with sf2dlib).
But X and Y are always the same.

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <math.h>
#include <3ds.h>
#include <sf2d.h>

int main(){
   srand(time(NULL));

   xC = rand() % 320;
   yC = rand() % 240;
}

the code is very simplified. Can anyone explain me why I have this issue ? thanks.

 

[Rinnegatamante]

Hi, I'm using the rand() function to determine random x and y positions (I'm working on a project with sf2dlib).
But X and Y are always the same.

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <math.h>
#include <3ds.h>
#include <sf2d.h>

int main(){
   srand(time(NULL));

   xC = rand() % 320;
   yC = rand() % 240;
}

the code is very simplified. Can anyone explain me why I have this issue ? thanks.

Try to change time(NULL) with osGetTime() and see if it change something (don't know if time is already available in ctrulib.)

 

[Coto]

well:

http://www.tutorialspoint.com/c_standard_library/c_function_srand.htm

the seed you give to srand is static in that example

 

[Slashcash]

Hi, I'm using the rand() function to determine random x and y positions (I'm working on a project with sf2dlib).
But X and Y are always the same.

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <math.h>
#include <3ds.h>
#include <sf2d.h>

int main(){
   srand(time(NULL));

   xC = rand() % 320;
   yC = rand() % 240;
}

the code is very simplified. Can anyone explain me why I have this issue ? thanks.

It seems perfectly fine to me. Or the time() function is broken on 3ds (it would surprise me since it's from the standard library) or the problem is somewhere else in the code.

 

[randomdev]

Okay thanks !

Try to change time(NULL) with osGetTime() and see if it change something (don't know if time is already available in ctrulib.)

osGetTime() is a different seed, but always give the same numbers (different from time(NULL) of course)...

well:

http://www.tutorialspoint.com/c_standard_library/c_function_srand.htm

the seed you give to srand is static in that example

Thanks for the information.

--------------------- MERGED ---------------------------

It seems perfectly fine to me. Or the time() function is broken on 3ds (it would surprise me since it's from the standard library) or the problem is somewhere else in the code.

I hope no

 

[Slashcash]

I hope no

Wait! Are you trying to get different random values for x and y? Because the code you wrote obviuosly gives the same x and y values.

If you want to get different values you have to do:

srand(time())

x = rand()

srand(time())

y = rand()

(obviuosly pseudocode)

 

[randomdev]

Wait! Are you trying to get different random values for x and y? Because the code you wrote obviuosly gives the same x and y values.

If you want to get different values you have to do:

srand(time())

x = rand()

srand(time())

y = rand()

(obviuosly pseudocode)

x and y values are differents, it's just always the sames (they are differents, but if I restart the homebrew, it will be the same set of values...)

 

[Slashcash]

x and y values are differents, it's just always the sames (they are differents, but if I restart the homebrew, it will be the same set of values...)

Sorry, my bad, my code was stupid. Effectively the code seems fine. Have you tried to print the seed returned by time() ? If you get a different seed everytime but rand() always give you the same sequence there is something wrong with rand() on 3ds (highly unlikely) or...somewhere else in your code? This is really strange.

 

[Gocario]

I tested that, and it worked well.

About your program, does it run well on Citra?
If so maybe your 3ds clock has a problem.