Looping through an array

Question

Can someone please explain to me why the answer to this is 0 and not 3.? When looping through the array, doesn’t it stop at 3? Wouldn’t 3 therefore be what I multiplied?

var arr = [1,2,3,4];
var x = 1;
for (var i = 0; I < arr.length; i++); {
x*=i;
}
alert (x);

Answer 1

It doesn't stop after the first iteration. Observe the code carefully. The loop content is

x *= i

and the value of x is printed after the loop ends.

1 multipled by 0 is 0. 0 is assigned to x.
0 multipled by 1 is 0. 0 is assigned to x.
0 multipled by 2 is 0. 0 is assigned to x.
0 multipled by 3 is 0. 0 is assigned to x.

x is printed.
0 is printed.

Answer 2

On the first iteration, the value of i is 0.

Anything multiplied by 0, is 0.

Answer 3

It doesn't stop.
after the first iteration x=0
then i =1,2,3,4 and

x = x*i =0
That's why its 0

Answer 4

By the way, the alert function is outside of the for loop.

Answer 5

So it stops after the first iteration not the last? I thought it would loop through them all. So the answer would be 0123. Thanks Hardy

Answer 6

Got it!! Thanks Hatsy. Perfect explanation. Thank you all.