Function having undefined variable in nested for loop

Question

When I run this, it claims x is undefined on the on the line with the for loop.

Full code:

function getCustomerNumbers() {
    var customerNumbers = [];
    customerNumbers.push(12, 17, 24, 37, 38, 43);
    return customerNumbers;
}
function getWinningNumbers() {
    var winningNumbers = [];
    winningNumbers.push(12, 17, 24, 37, 38, 43);    
    return winningNumbers;
}
function checkNumbers(x, y) {    
    var matches = 0;
    for (i=0; i<x.length; i++) {
        for (j=0; j<y.length; j++) {
            if (x[i] == y[j]) {
                matches++;
            }
        }
    }
    return matches;
}
function displayResult() {
    checkNumbers(getWinningNumbers(), getCustomerNumbers())
    alert("This Week's Winning Numbers are:\n\n" + getWinningNumbers().toString() + 
    "\n\nThe Customer's Number is:\n\n" + getCustomerNumbers().toString() + "\n\nNumber of Matches:" + checkNumbers());
}
function init() {
    displayResult();
}
window.onload = init;

Later it runs, with arrays going into values x and y. It ran fine when it was just x as an array and one for loop.

Anyone know what is wrong here?

What are you putting in for x when it doesn't run? ".length" only works on arrays or certain collections. — Matt Runion
– Matt Runion, Commented Feb 12, 2015 at 16:24
function checkNumbers(var x, var y) -- why do you have var listed in the parameters? It should be function checkNumbers( x, y) — ps2goat
– ps2goat, Commented Feb 12, 2015 at 16:30
@ps2goat You've just found the missing vars for i and j? — Teemu
– Teemu, Commented Feb 12, 2015 at 16:32
Check my answer. you're not passing anything in for x and y on the second call to checkNumbers — ps2goat
– ps2goat, Commented Feb 12, 2015 at 16:40

ps2goat · Accepted Answer · 2015-02-12 16:36:34Z

2

Your posted code is still missing something, as the first function is missing.

The next thing I found was the second call to checkNumbers doesn't pass anything in.

function displayResult() {
    checkNumbers(getWinningNumbers(), getCustomerNumbers())
    alert("This Week's Winning Numbers are:\n\n" + getWinningNumbers().toString() + 
    "\n\nThe Customer's Number is:\n\n" + getCustomerNumbers().toString() + "\n\nNumber of Matches:" + checkNumbers()); //<-- where are the parameters?
}

Working code:

function getCustomerNumbers(){
var customerNumbers = [];
    customerNumbers.push(12, 17, 24, 37, 38, 43);
    return customerNumbers;
}
function getWinningNumbers() {
    var winningNumbers = [];
    winningNumbers.push(12, 17, 24, 37, 38, 43);    
    return winningNumbers;
}
function checkNumbers(x, y) {    
    var matches = 0;
    for (var i=0; i<x.length; i++) {
        for (var j=0; j<y.length; j++) {
            if (x[i] == y[j]) {
                matches++;
            }
        }
    }
    return matches;
}

function displayResult() {    
    alert("This Week's Winning Numbers are:\n\n" + getWinningNumbers().toString() + 
    "\n\nThe Customer's Number is:\n\n" + getCustomerNumbers().toString() + "\n\nNumber of Matches:" + checkNumbers(getWinningNumbers(), getCustomerNumbers())
         );
}

displayResult();

answered Feb 12, 2015 at 16:36

ps2goat

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2 Comments

cfleming93 Over a year ago

apologies, left out the top line where I called the function

ps2goat Over a year ago

Then the code you posted is different from what you're using. My snippet works.

Jamiec · Accepted Answer · 2015-02-12 16:42:23Z

0

You're calling checkNumbers twice - the first time passing in valid values for x & y and the second time passing in nothing

function displayResult() {
    // Good, but ignores result
    checkNumbers(getWinningNumbers(), getCustomerNumbers()) 
    //Nothing passed in
    alert("This Week's Winning Numbers are:\n\n" + getWinningNumbers().toString() + 
    "\n\nThe Customer's Number is:\n\n" + getCustomerNumbers().toString() + "\n\nNumber of Matches:" + checkNumbers()); 
}

answered Feb 12, 2015 at 16:42

Jamiec

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