Question

I wrote the following code that outputs the sum of squared iterating numbers:

(function () {
    var i = 4, sum = 0; 
    while(i--) sum+=i*i;
})();
console.log(sum);

The problem is I get the following error in console: sum is undefined unless I take the sum out and declare it as global scope:
//this works but this is not what I want.

sum = 0;    
(function ( ) {
    var i=4 
    while(i--) sum+=i*i;
})();
console.log(sum);

Could some one help me understand?
Thanks

Answer 1

Because you are accessing sum outside your function scope at the line:
console.log(sum), where sum is not visible.

If you do not want to put sum in global scope, then you got to take the statement console.log(sum) within the function scope.