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

int flip(void);

int main(void)
{
   srand((unsigned) time (NULL));
   for (int i = 0; i < 15; i++) {
      printf("%d: %d\n", i, flip());
   }
   return 0;
}

int flip(void)
{
   double min = -1.0;
   double max = 2.0;

   double r1 = ((double) rand()) / ((double) RAND_MAX) * (max - min);

   int r2 = ((int)r1)+min;

   return r2;
}