factorial of a number

Question

I have the following code but it is not giving perfect result for factorial can u find it out plz

Answer 1

I am not sure why no one used dynamic programming to answer this, it's by far the most efficient way to build something on a factorial in my view.

 var mem = [];

 function fact(num)
 {
    var x = parseInt(num);

    if (x == 0 || x == 1) return 1;

    mem[x] = x * fact(x-1);

    return mem[x];
 }