Infinite while loop

jw2 · #1 (**permalink**) 11-01-11, 06:52 PM

Hi everyone,

I'm a beginner and have been experimenting with loops in javascript. Could anybody point me in the right direction as to why my code returns a script error/infinite loop?

Code:

<html>
<script>

// Date:        November 2011
// Purpose:     Get an odd number between 25 and 75

var num=0;

while ((num<25) || (num>75) && (num%2 ==0));
{
	num = eval(prompt("Enter an odd number between 25 and 75"));
}

alert(num + " is an odd number between 25 and 75");

           
</script>
</html>

Thanks!

KatanaPL · #2 (**permalink**) 11-01-11, 11:46 PM

I don't know JS but I'm thinking that you are asking the user to type a number when num is <25 OR >75 and the mod2 is 0
BUT num is 0 at the start, so it will always ask for a number.
You should ask the user for a number THEN check if the number is <25, >75 and mod2 is 0.

Alert should be inside the loop, not the prompt

Code:

<html>
<script>

// Date:        November 2011
// Purpose:     Get an odd number between 25 and 75

var num=0;

num = eval(prompt("Enter an odd number between 25 and 75"));

while ( ((num>=25) || (num<=75)) && (num%2 ==1))
{
    alert(num + " is an odd number between 25 and 75");
    break;
}



           
</script>
</html>

It's working now