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

int fib_recur (int);
int fib_loop (int);

int main (int argc, char **argv) 
{
  int limit;

  if (argc < 2) {
    printf ("USAGE: fib <limit>\n");
    exit (1);
  }
  limit = atoi (argv[1]);

  printf ("fib recursion: %i\n", fib_recur (limit));
  printf ("fib loop: %i\n", fib_loop (limit));
  
  return 1;
}

int fib_recur (int limit) 
{
  if (limit == 0)
    return 0;
  if (limit == 1)
    return 1;
  if (limit > 1)
    return fib_recur (limit - 2) + fib_recur (limit - 1);
  return -1;
}

int fib_loop (int limit) 
{
  int fib_2, fib_1, i, subtotal;

  if (limit == 0)
    return 0;
  if (limit == 1)
    return 1;
  fib_2 = 0;
  fib_1 = 1;
  i = 1;
  do {
    subtotal = fib_2 + fib_1;
    fib_2 = fib_1;
    fib_1 = subtotal;
    ++i;
  }
  while (i < limit);

  return subtotal;
}