Fibonacci

[#1]

I'm using Javascript to create the Fibonacci function and the performance is bad and the program crashes with Fibonacci(45) and upper on an 8 core i7 CPU second generation. I've noticed Javascript don't use my CPU at 100% only at 12%.

Isn't there a good way to create a Fibonacci function with good performance?

function Fibonacci(x)

{

          if (x == 0)

          {

              return 0;

          }

          else if (x == 1)

          {

              return 1;

          }

          else

          {

              return Fibonacci(x - 1) + Fibonacci(x - 2);

          }

}

[#2]

Yes, try not using recursion, something like this:

function Fibonacci(x)

{

     r = 0;

     for i = 1 to x

     {

          r = r + i;

     }

     return r;

}

[#3 · Accepted solution]

My own answer to my own question:

function FibIter(n)

{

    u = 0;

    v = 1;

    if(n==0) return 0;

    if(n==1) return 1;

    for(i = 2; i <= n; i++)

    {

        t = u + v;

        u = v;

        v = t;

    }

    return v;       

}