Where I go wrong?

Question

I have to write a code for a function that calculate sum of only positive numbers or if there is nothing then return 0 here is code
function positiveSum(arr) {
var sum;
for(let i=0; i <= arr.length; i++){
let temp = arr[i];
if(temp > 0){
sum+=arr[i]
}
else {
sum = 0;
}
}
return sum;
}

Answer 1

And initialize <sum> once just before the loop starts

var sum = 0;

Answer 2

when temp is not positive, you are reseting the sum to 0

Answer 3

Your code is almost correct. You need to initialize the value of sum to 0 before starting the loop. If arr is an empty array, then sum should remain 0, otherwise it will result in undefined.

Here is the corrected code:

function positiveSum(arr) {
var sum = 0;
for(let i=0; i < arr.length; i++){
let temp = arr[i];
if(temp > 0){
sum+=arr[i]
}
}
return sum;
}