Odd numbers

[Flagada]

Hi,

This might be a stupid question: How do I check if an integer value is odd?

Thanks.

 

[TonyGroves]

[tt]
int n=123;
if(n/2*2!=n)
printf("odd");
[/tt]

 

[TonyGroves]

Silly me, I forgot the % operator:
[tt]
int n=123;
if(n%2)
printf("odd");
[/tt]

 

[Flagada]

Okay thanks, it solved my problem.

So if I get it right, n%2 means that n cannot be didived by 2 ? And does n%3 then means that n cannot be divided by 3 ?

Or am I wrong?

Bill

 

[itsgsd]

n%m means n modulo m (abbreviated n mod m)
n%2 means n modulo 2
n%3 means n modulo 3

The modulo is simply the remainder, so if the modulo is 0, the number n is exactly divisible by m. If n is not divisible by m, then there is a remainder.

Hence, (6%2) equals 0, (5%2) equals 1, (5%3) equals 2 etc. To clarify the example above by TonyGroves:

int n=123;
if (n%2)  // literally means if (n%2 != 0)
  printf ("odd");

Hope that helps to clarify.

 

[Flagada]

Ok, now i got it. Thanks.

Bill

 

[Totte]

As it is a question of integers it's equally usefull to simply do a "AND" with 0x01.

if(n & 1) /* Do the odd thing */;
else /* Do the even thing */;

It's faster than '%' as it requires no division.

Totte
Keep making it perfect and it will end up broken.