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JavaScript

Posted by Terrance Corley
Terrance Corley
11,990 Points

Can someone explain why this code returns an endless loop?

var number = randNum(3);
var guess;
var guessCount = 0;

function randNum( upper ) {
  var getNumber = Math.floor( Math.random() * upper ) + 1;
  return getNumber;
}

do {
  guess = parseInt( prompt('Can you guess the number?') );
  guessCount += 1;
} while ( guess !== number )

document.write('You guessed it! ' + 'It took you ' + guessCount + ' tries to guess the number ' + number);

3 Answers

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

The loop only lasts as long as it takes to guess the number, it's not really "endless" unless you always put in a wrong guess.

Now if the number range were much larger, it might be very hard to guess the number and it might seem endless!

Terrance Corley
Terrance Corley
11,990 Points

That's the thing though. I'm guessing a number 1-3 but I can never guess the number. It seems the loop doesn't end even when I guess the correct number, but I can't find the error in my code.

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

Odd, I tried it several times and it always ended for me, though sometimes I had to guess all 3 times. Did you try checking the browser console for errors?

Terrance Corley
Terrance Corley
11,990 Points
Terrance Corley
Terrance Corley
11,990 Points

I just figured it out. My script was fine, it was an external stylesheet that was causing my bug, facepalm. Haha, thanks for your help!

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

I'd be curious to know how a stylesheet could have prevented the program from working!

Terrance Corley
Terrance Corley
11,990 Points
Terrance Corley
Terrance Corley
11,990 Points 
body {
  font-size: 1.4rem;
  padding: 0 400px;
}

form {
  max-width: 500px;
  margin: 5em auto 0;
}

form fieldset {
  border: 2px solid lightblue;
  border-radius: 5px;
  padding: 1em;
}

form fieldset  > * {
  display: block;
}

input {
  margin-bottom: 1.2em;
  padding: 0.5em 0.6em;
}

This code was in an external css file linked to my index.html. I had forgot it was linked. The body of my index.html file has nothing in it except for the linked script. I'm in the same boat as you as to not understanding why this would cause issues with the script...but at least it works now. :)

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

I got the exact same (correct) behavior with the CSS. But it did look prettier!

Terrance Corley
Terrance Corley
11,990 Points

Weirrrrrrd haha. I'm off to my day job but I'll definitely play around with the code later. Perhaps it was a browser issue (but I'm using chrome). Thanks again for all your help, Steven!