Dianna - 1 year ago 72
Javascript Question

# How to find the sum of arrays entered by user?

How do I find the sum of the numbers entered by the user in the numbersBox?
If the user entered "5, 3, 6, 1" in the numbersBox, I should be getting the answer "15" in the sumBox after clicking the "Find Sum" button. I cannot figure out how to add up all the array elements and what should I be putting in the for loop.

``````function findSUM(){
list = numbersBox.value.split(",");

var sum = list[0];
for(var i = 0; i < list.length; i++){
list[i] = parseInt(list[i]);

if(list[i] < i){
max += list[i];
}
}
sumBox.value = sum;
}
``````

``````<label>Write numbers separated by commas:</label>
<br><br>
<input type="text" id="numbersBox" />

<label>Sum of all numbers:</label>

<input type="text" id="sumBox" />

<button type="button" onclick="findSUM();">Find Sum</button>
``````

Thank you. I will really appreciate all your help.

You need to converts all array elements to `Number` here `Array.prototype.map()` can be used. Iteration should start with 2nd index as variable `sum` is initialized with value if number at first index.

``````function findSUM() {
//Create a list of Numbers
var list = document.getElementById('numbersBox').value
.split(",")
.map(function(x) {
return isNaN(x) ? 0 : Number(x);
});

//Init with first no
var sum = list[0];

//Iteration starts wit 2nd element
for (var i = 1; i < list.length; i++) {
sum += list[i];
}
document.getElementById('sumBox').value = sum;
}``````
``````<label>Write numbers separated by commas:</label>
<br>
<br>
<input type="text" id="numbersBox" />
<label>Sum of all numbers:</label>
<input type="text" id="sumBox" />
<button type="button" onclick="findSUM();">Find Sum</button>``````

Recommended from our users: Dynamic Network Monitoring from WhatsUp Gold from IPSwitch. Free Download