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

long count = 0;

void *counter(void *arg) {
  long steps = (long)arg;
  for(long i=0; i<steps; i+=1) count += 1;
  return NULL;
}

int main(int argc, char *argv[]) {
  if (argc != 3) {
    fprintf(stderr, "USAGE: %s <threads> <steps_per_thread>\n", argv[0]);
    return 1;
  }
  long t = atol(argv[1]);
  long spt = atol(argv[2]);

  pthread_t *tid = calloc(t, sizeof(pthread_t));
  for(long i=0; i<t; i+=1) pthread_create(&tid[i], NULL, counter, (void *)spt);
  for(long i=0; i<t; i+=1) pthread_join(tid[i], NULL);
  free(tid);

  printf("%ld * %ld = %ld (%.4g%% of expected)\n", t, spt, count, 100.0*count/(t*spt));
  return 0;
}