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How to detect if number has a decimal point or not
Hi I am currently trying to find out weather a number is odd or even, to do this I have divided it by two and want to see if it has a decimal point or not. The problem is i'm not 100% sure how I would achieve that.
My code is bellow if i am not explaining it well enough.
using UnityEngine; using System.Collections;
public class Math : MonoBehaviour {
decimal Number = 3;
decimal number2 = 2;
// Use this for initialization
void Start () {
Number = Number / number2;
print (Number);
if (Number Has a decimal Point){
dosomething;
}
Answer by Reder13 · Mar 25, 2015 at 03:51 PM
you need to use the mod operator %
this gives you the remainder of two numbers
so number % number2 == 0 if it is even and number % number2 != 0 means odd
I am a bit lost, how would I put this number into context
I would do something like this:
float Number = 3;
// Use this for initialization void Start () {
print (Number % 2);
if ( Number % 2 != 0){ // if Number has a decimal
//dosomething;
}
you dont really need to have Number2 for your code since you know its going to be a 2
the code above prints out the remainder of Number and 2 (1 in this case) and since 1 isnt equal to 0 Number must be odd thus it enters the body of the if statement to do something.
@Reder13 the comment should say "if Number is odd" rather than "if Number has a decimal".
Yes and no in the current context yes your right it would be if Number is odd @Bonfire Boy. However I was thinking if Number were say 3.37 or some other value other than an int then it would be true if number has a decimal.
Thanks for re$$anonymous$$ding me to clarify that.
In the case you want to use Interger values only for Number just change the : float Numbers to int Numbers and the comment to // if Number is odd
@Reder13 I beg your pardon. The question talks about odd and even, so I had integers in my head and missed the fact that the code was all (strangely?) not using integers. Thanks for the clarification.
Answer by Bonfire-Boy · Mar 26, 2015 at 01:14 AM
There are actually two questions here.
"Odd" and "even" are concepts that only apply to integers.
One way to test whether a number is odd or even is as Reder13 says, to use the mod operator. But it's only when you're dealing with integers, that you can do it with a single test...
EParity OddOrEven( int i )
{
return ( i % 2 == 0 )?( EParity.Even ):( EParity.Odd );
}
But note that this only works because for integers, i%2 can only take the values 1 and 0.
Alternatively, and probably faster, you could just look at the ones bit
EParity OddOrEven2( int i )
{
return ( ( i & 1 ) == 0 )?( EParity.Even ):( EParity.Odd );
}
But you're using decimals in your code, so there's a third possibility and you need to do 2 tests.
EParity OddOrEven( float f )
{
if ( f % 2 == 0 )
return EParity.Even;
else if ( f % 2 == 1 )
return EParity.Odd;
return EParity.Neither;
}
The bitwise version only works with integers so to use that with floats you need to check if it's an integer first..
EParity OddOrEven2( float f )
{
int i = Mathf.FloorToInt( f );
if ( f != float( i ) )
return EParity.Neither;
return OddOrEven2( i );
}
...the first part of which is a way of doing what the question in the title asks for. Whether or not a float has anything after the decimal point is the same as asking if it's (not) an integer, and you can do that by casting back and forth then comparing.
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