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

// for random numbers of 1 to RANGE
#define RANGE 1000

int main(void)
{
   int rand_num;
   int fd;
   int i;
   int which;
   int check[RANGE];
   int done  = 0;
   int iters = 0;

   for (i = 0; i < RANGE; i++)
   {  check[i] = 0;
   }

   fd = open("/dev/urandom", O_RDONLY);
   if (fd != -1)
   {  read(fd, &rand_num, 4);
   }
   else
   {  printf("can't read from /dev/urandom!\n");
      return 1;
   }

   srandom(rand_num);  // set the seed value

   while(!done)
   {  iters ++;
      which = 1 + (int) ((RANGE + 0.0)*random()/(RAND_MAX + 1.0));
      printf("iter: %d rand: %d\n", iters, which);
      check[which - 1] = 1;
      done = 1;

      for (i = 0; i < RANGE; i++)
      {  if (check[i] == 0)
         {   done = 0;
   }  }  }

   printf("took %d iterations to find all values\n", iters);
   return 0;
}

-- MattWalsh - 29 Nov 2004