Question

Possible Duplicate:
calling rand() returning non-random results

In my workshop I need to takes 2 different random numbers but I get 2 same random number.

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int random1_6(){
 int k;
 srand(time(0));
 k=((rand()%6)+1);
 return k;
}
int main(void){
 int a,b;
    a=random1_6();
    printf("%d.\n",a);
    b=random1_6();
    printf("%d.\n",b);
return 0;
}

How to get 2 different random number?

Answer 1

A non-cryptographic random number generator (RNG) is not truely random but it generates random-like numbers based on a seed.

What you do is initializing the RNG with the same seed two times, so you get the same results. Seed the RNG just once, e.g. at program start, and you will get random-like different results.

Edit: a code like follows should work:

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

int random1_6(){
  return ((rand() % 6) + 1);
}

int main(void){
  int a,b;
  srand(time(NULL));

  a = random1_6();
  printf("%d.\n",a);

  b=random1_6();
  printf("%d.\n",b);

  return 0;
}