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function averageCalculator (numvalues) {

    for(i=0, i <= numvalues, i++>) {
    var score = prompt("input the score")
    result1 += score;

    }

    alert(result1 / 3);
}

this function is later triggered by a button with onclick="averageCalculator (2)

<input type="button" value="Click for the average" onclick="averageCalculator (2)">

any ideas why its not working? it should prompt you for 2 values and then alert you with the average. not sure whats wrong.

function averageCalculator (numvalues) {

    for(i=0, i <= numvalues, i++>) {
    var score = prompt("input the score")
    result1 += score;

    }

    alert(result1 / 3);
}

this function is later triggered by a button with onclick="averageCalculator (2)

<input type="button" value="Click for the average" onclick="averageCalculator (2)">

any ideas why its not working? it should prompt you for 2 values and then alert you with the average. not sure whats wrong.

• javascript
• function
• average

Share Improve this question Follow asked Jan 27, 2012 at 10:39 Nic MeiringNic Meiring 88255 gold badges1616 silver badges3333 bronze badges 3

• What is happening now? Wrong answer or code not executing? – bnieland Commented Jan 27, 2012 at 10:42
• 1 You probably want to change the alert to alert(result1 / numvalues); – Richard Dalton Commented Jan 27, 2012 at 10:46
• im getting ReferenceError: averageCalculator is not defined so code not executing. seems to be defined as a function though... not sure – Nic Meiring Commented Jan 27, 2012 at 10:50

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 4

Your code has multiple issues. The for loop is not well-formatted and you need to terminate statements with a semi-colon. Also, you need to declare variables. And your loop will run numvalues+1 times which is why I removed the = in your loop. Also if you want to calculate an average you want to divide by numvalues.

function averageCalculator (numvalues) {
var result1 = 0;
for(let i=0; i < numvalues; i++) {    
    var score = prompt("input the score");   
    result1 += score;    
}
alert(result1 / numvalues);
}

numvalues represents the number of inputs you want to calculate average for.

On top of the invalid syntax you will run into a mon "problem" with javascript here. The inputs are treated as strings and instead of being added they will be concatenated. Providing 2 and 2 as scores will result in 11. 2 concatenated with 2 = 22 / 2 = 11. You need to cast the value to a number explicitly before adding them together:

function averageCalculator (numvalues) {
var result1 = 0;
for(i=0; i < numvalues; i++) {    
    var score = prompt("input the score");   
    result1 += Number(score);    
}
alert(result1 / numvalues);
}

The code above will correctly return 2.

The syntax of your for-loop is wrong:

for(i=0, i <= numvalues, i++>) {

should be

for(i=0; i <= numvalues; i++) {

Tip: Also, it's better to use

for(var i=0; i <= numvalues; i++) {

since then i will be a local variable instead of a global one.

Try like this

for(var i=0; i <= numvalues; i++){}

An alternative solution (using a functional programming libary, like Underscore.js):

function averageCalculator(numValues) {
    var numbers = _.map(_.range(numValues), function(element) {
        return +prompt('input the score');
    });

    var result = _.reduce(numbers, function(memo, number) {
        return memo + number;
    }, memo);

    alert(result / 3);
}

While a little bit more plicated (and less efficient), you'll get rid of loops altogether.

EDIT

The +prompt('input the score') does effectivly the same as Number(prompt('input the score')).

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