#include <library.h>

/*
  int f(const int n)
  { if (n <= 1)
      return 1;
    const int a = f(n-1);
    const int b = f(n-2);
    return a + b; }

  // That version is incredibly slow. Why?
*/


// In this version, "accidentally" replace the == with =
// what happens and why?

int f(int n, int a, int b)
{ if (n == 0)                   
    return b;
  return f(n-1, a+b, a); }

int f(int n)
{ return f(n, 1, 1); }

/*
  int f(const int n)
  { int i = 0, a = 1, b = 0;
    while (i < n)
    { const int temp = a + b;
      b = a;
      a = temp;
      i = i + 1; }
    return a; }

  // Do you really think that's any better? or easier to understand?
  // I don't
*/

void main()
{ int x = 1;
  while (true)
  { cout << x << ": " << f(x) << "\n";
    x = x + 1; } }