add values to one variable with for loop totalSum Javascript - Stack Overflow

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I have some values that e randomized to an variable. Now i want to add every value to each other to get an total sum but the loop wont add them together.

The index variable work when i console log it. but not the total sum of a current value and the index value. Any tips ?

This is the loop // The indexValue is values I get from an array//

  var indexValue = index;  // Random number from 1 - 10
    var totalSum = 0;

   for(var x = 0; x <indexValue; x++){

   var currentValue = index[x];
   totalSum += currentValue;
    }

    console.log(totalSum);

I have some values that e randomized to an variable. Now i want to add every value to each other to get an total sum but the loop wont add them together.

The index variable work when i console log it. but not the total sum of a current value and the index value. Any tips ?

This is the loop // The indexValue is values I get from an array//

  var indexValue = index;  // Random number from 1 - 10
    var totalSum = 0;

   for(var x = 0; x <indexValue; x++){

   var currentValue = index[x];
   totalSum += currentValue;
    }

    console.log(totalSum);

• javascript

Share Improve this question Follow asked Feb 6, 2013 at 17:52 DymondDymond 2,28777 gold badges4646 silver badges8282 bronze badges 4

• 1 I think it should be var indexValue = index.length; – Pointy Commented Feb 6, 2013 at 17:53
• What is index? What exactly does it mean if a variable "does not work"? – Felix Kling Commented Feb 6, 2013 at 17:53
• 1 on your first line, were u intending to do "var indexValue = index.length" ? – Dogoku Commented Feb 6, 2013 at 17:56
• have tried with index.length. But no luck – Dymond Commented Feb 6, 2013 at 18:04

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2 Answers 2

Sorted by: Reset to default 2

I'm assuming since you're referencing index[x] that index is an array. If so, you are assigning the wrong value to indexValue. Try this:

var indexValue = index.length;

What this does is assign the length of the array to the variable indexValue. Now the for loop will run from 0 to n where n is the length of the array.

This should get you the values you need.

Hope this helps.

EDIT:

Below is a link to a jsFiddle I created with your example and the code explained:

jsFiddle

var index = [1,2,3,4,5];  

var indexValue = index.length;  // It's imperative that this is an array
var totalSum = 0;

for(var x = 0; x <indexValue; x++){
    totalSum += index[x];
}

alert(totalSum);

The code above is a modified version of what you posted. The current value is not needed and has been removed. In this case, I created an array and stored the values in index. The length is puted, and the values are added together.

For the easy sake of testing, I changed console.log(totalSum); to alert(totalSum);. It will produce the same value just the same.

Just a reference note on console.log. Some browsers (mainly IE) who do not attach the debugger to the process automatically without a page refresh will through an error as console will be undefined. Here is a quick fix for that:

if(window.console && window.console.log) {
    console.log(totalSum);
} 

This checks that (a) the console object is attached to the global window object and (b) that the log object of console is attached to the console object.

you probably want something like this:

var sum = 0;
for (var i=0; i < index.length; i++) {
    sum += index[i];
}
console.log(sum);

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