#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

#define TRUE 1
#define FALSE 0

int main(void)
{
  const int ONE_BILLION = 1000000000;
  const int ONE_HUNDRED_MILLION = 100000000;
  int billions_counter = 0;
  int num_billions = 0;
  int i = 0;
  int keep_counting = TRUE;
  pid_t pid = 0;
  
  printf("How many billion should we count to?");
  scanf("%d", &num_billions);
  pid = getpid();
  
  while(keep_counting)
  {
    for(i = 1; i < ONE_BILLION; i++)
    {
      if(i  % ONE_HUNDRED_MILLION == 0)
      {
        printf("pid %d: %d billion, %d hundred million\n", pid, billions_counter, (i / ONE_HUNDRED_MILLION));
      }
    }
    billions_counter++;
    printf("pid %d: %d billion.\n\n", pid, billions_counter);
    if(billions_counter >= num_billions)
    {
      keep_counting = FALSE;
    }
  }
  printf("We just counted to %d billion.\n", num_billions);  
}