Why isn't my JavaScript loop working?

Question

The loop is supposed to take the price of each book, add it to the total, and then put the average on the page for each book until the user enters in "N"

<script type="text/javascript">
var ct = 1;
var yesORno = "Y";
while (yesORno = "Y"){
    book = prompt("What is the price of book #" + ct, 0);
    total = parseInt(book) + total;
    ans = total / ct;
    document.write("<p>With book #" + ct +" The average is " + ans + "</p>");
    ct = ct + 1;
    yesORno = prompt("Would you like to continue? (Y/N)", "")
}
</script>

while (yesORno = "Y"){ should be while (yesORno === "Y"){ Use jshint.com to find common errors in your code. — Blue Skies
– Blue Skies, Commented Oct 28, 2013 at 1:20

Guilherme Sehn · Accepted Answer · 2013-10-28 01:20:31Z

8

You should change your while condition to:

while (yesORno == "Y")

Using only = will make it assign 'Y' value to yesORno and return itself, which is evaluated as true and makes it run forever.

answered Oct 28, 2013 at 1:20

Guilherme Sehn

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Comments

Waclock · Accepted Answer · 2013-10-28 01:20:41Z

3

var ct = 1;
var yesORno = "Y";
while (yesORno == "Y"){
    book = prompt("What is the price of book #" + ct, 0);
    total = parseInt(book) + total;
    ans = total / ct;
    document.write("<p>With book #" + ct +" The average is " + ans + "</p>");
    ct = ct + 1;
    yesORno = prompt("Would you like to continue? (Y/N)", "")
}

Look at the third line.

answered Oct 28, 2013 at 1:20

Waclock

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Comments

plalx · Accepted Answer · 2013-10-28 01:28:38Z

3

Like others stated, you have used the assignment operator = instead of the equality operator == or the strict equality operator ===.

However, you could also refactor your code using a do while loop instead. That would remove the need of having a yesORno variable.

do {
    //...
} while(prompt("Would you like to continue? (Y/N)", "") === 'Y')

answered Oct 28, 2013 at 1:28

plalx

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