I dont want this code to show me NaN can someone help me?

Question

Const marks = [12, 13, 15, 17]
Let sum =0
For (let i=0; i<=marks.length;i++){
sum += marks[i]
}
Console.log(sum)

Answer 1

amir hosein kazazi

As array index start from 0 and you have 4 elements so your index would be 0 1 2 3

But you are trying to access 4th index which has nothing so you get NaN.

So change i <= to i <

Answer 2

One tip, use console.log(i) inside loop, or in any code where have unespected output or error.
So you can see what are your data