/*

     VOTE for your favorite Fibonacci function!

     Rank 1-3, 1 is most favorite, 3 is least favorite:
*/


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

int fib1(int n)
{ if (n<2) return 1; else return fib1(n-1) + fib1(n-2); }


int fib2(int n, int a, int b)
{
  if (n<2) return b; else return fib2(n-1,b,a+b);
}
//  always call with a=1, b=1 initially


int fib3(int n)
{
  int a = 1, b = 1;
  int temp = 0; // for swap
  while (n>1) { temp = a;  a = b; b = temp+b; n--; }
  return b;
}


int main(int argc, char**argv)
{
  int n = atoi(argv[1]);
  printf("with non-tail recursion: %d\n", fib1(n));
  printf("with tail recursion: %d\n", fib2(n,1,1));
  printf("with while loop %d\n", fib3(n));
  exit(0);
}