Which one is better and why?

rjddude1

Is recursive function for calculating Fibonacci series or iterative function is better?
ITERATIVE:

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int fibonacci_iterative(int n)      //Iterative formula for fibonacci series

{

  int f0 = 0;

  int f1 = 1;

  int i, fn;
 
  if (n == 0)

        return 0;

  if (n == 1)

        return 1;
 
  for(i = 2; i <= n; i++)

  {

    fn = f0 + f1;

    f0 = f1;

    f1 = fn;

  }

  return f1;

}

RECURSIVE

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int fibonacci_recursive(int nNumber)   //Recursive formula for fibonacci series

{

    if (nNumber == 0)

        return 0;

    if (nNumber == 1)

        return 1;

    return fibonacci_recursive(nNumber-1) + fibonacci_recursive(nNumber-2);

}

donbock

The stack usage for the iterative function is invariant -- it is the same regardless of the input argument.

The stack usage for the recursive function is proportional to the input value.

The recursive function is smaller and easier to understand.

I haven't done an analysis, but it looks to me like the recursive function will be slower than the iterative function.

Which is "better"? It is a trade-off between these factors. In some contexts, ease of understanding will trump everything else; in other contexts (most notably embedded systems), stack usage trumps everything else.

Which one is better and why?

re: Which one is better and why?

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