Unexpected infinite loop

Question

This code runs for infinity, why?

    function f(n){
        i=0;
        if (n==2){
            while(i<2){
                f(i);
                i++;
            }
        }
    }

if n!=2 the function should do nothing and if n equals 2 the function calls f(0) and f(1) so it should stop after that but you only get infinite loop when you run it.

any one could tell why?

edit: there is nothing outside the function.

and no need for better code.Just asking why.

Answer 1

You can fix it by changing

i=0;

to

var i=0;

Your i variable is global (or at least its scope is external to f, so it's shared by all calls of the function). When n is initially 2, you enter the loop and this loop always resets i to 0 just before the increment. The sequence you have is thus

i = 0 // start of f
// enters loop for the first time with f(0)
i = 0 // start of f
i = 1 // i++
i <2 so loop again
i = 0 // start of f
i = 1 // i++
i <2 so loop again
i = 0 // start of f
i = 1 // i++
i <2 so loop again
i = 0 // start of f
i = 1 // i++
i <2 so loop again
i = 0 // start of f
i = 1 // i++
...

Answer 2

i is global. Declare it with var instead to keep it local to each instance. Otherwise, it is constantly reset to 0, so your while loop never ends.