How to determine if a number is odd or even in Java script

Question

Can anyone point me to some code to determine if a number in JavaScript is even or odd?

I'm trying to do something like:

if(intellect is even)
{
    var magic1 = intellect/2;
}
else
{
    var magic1 = (intellect-1)/2
}

var magicdamage = Math.floor(Math.random) * (intellect + weaponi) + magic1

number%2 would tell if zero then is even else is odd, this is how math works. I dont have time but I believe: first convert string to int then do the math in your if statement should work. — Michael Mao, Jun 05 '13 at 01:08
If you typed this exact same question on google you'd get the answer faster... just saying :) — Marlon Bernardes, Jun 05 '13 at 01:10

score 21 · Accepted Answer · answered Jun 05 '13 at 01:08

21

Use the modulus operator

if(intellect % 2 == 0)
{
  alert ('is even');
}
else
{
  alert('is odd');
}

answered Jun 05 '13 at 01:08

TGH

38,769
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score 8 · Answer 2 · edited May 23 '17 at 12:02

8

I think the most robust isEven function is:

function isEven(n) {
  return n == parseFloat(n) && !(n % 2);
}

which leads to:

function isOdd(n) {
  return n == parseFloat(n) && !!(n % 2);     
}

See Testing whether a value is odd or even

edited May 23 '17 at 12:02

Community

1
1

answered Jun 05 '13 at 02:01

RobG

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score 2 · Answer 3 · answered Jun 05 '13 at 01:08

2

if( var % 2 == 0){ /*even*/} else {/*odd*/}

Works for Java, Javascript and any other language. It's a very simple solution, that's why it often doesn't come into your mind until you've seen it somewhere.

The modulo operator % will return the remainder of a division. If the number being divided is even, the remainder is 0.

answered Jun 05 '13 at 01:08

rath

3,655
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There is no need to compare with 0 in a test like this. `if (num % 2)` returns `true` if *n* is odd. – RobG Jun 05 '13 at 01:24
You are right. I like to compare with 0 for added clarity – rath Jun 05 '13 at 01:29

francisco.preller · Answer 4 · 2013-06-05T02:56:11.250

2

Like this:

var i = 2;

if (i%2)
    // i is odd
else
    // i is even

edited Jun 05 '13 at 02:56

answered Jun 05 '13 at 01:10

francisco.preller

6,559
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You're right, why not :) Edited for elegancy – francisco.preller Jun 05 '13 at 02:55

Walter Macambira · Answer 5 · 2013-06-05T03:53:42.770

0

Try using this:

var number = 3;

if (number % 2)
{ 
   //it is odd
}
else
{
   //it is even
}

edited Jun 05 '13 at 03:53

answered Jun 05 '13 at 01:09

Walter Macambira

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19
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Sorry, as english is not my native language I was make this mistake. – Walter Macambira Jun 05 '13 at 03:54

How to determine if a number is odd or even in Java script

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