[JASS] IsInteger

[Bribe]

    function IsRational takes real r returns boolean
        return (R2I(r) == r)
    endfunction

Trying to figure out the accuracy of this thing. Are there any gotchas to be worried about?

 

[jk2pach]

function IsRational takes real r returns boolean
    return R2I(r) == r
endfunction

That should work, yeah. Only the () are useless.

Note: the "==" operator just take care about the first 3 numbers after the coma.

Example: R2I(1.254) == 1.254 will work (and return false) but R2I(1.0004) == 1.0004 will not work (the == will just check 1.000).

 

[Berb]

If you're not so confident in that method, I suppose you could try:

function IsInteger takes real number returns boolean
    return (number-R2I(number)) == 0
endfunction

 

[Cr34p]

pointless functions are pointless....

 

[PurplePoot]

This is actually a remarkably not pointless function even though it might look like one.

 

[Berb]

You're not really determining whether or not the value is an integer, rather whether a real number is a whole number. If there was a modulus operation then it would be even cooler:

if (yourNumber % 1 == 0) {
    // "yourNumber" is a whole number.

}

 

[Cr34p]

there actually is a mod function but no mod operator

 

[Berb]

The modulus function is slow.

 

[Bribe]

But it works, and it does the exact same thing as any mod operator. It's only slow because JASS is slow.

 

[BoneBreaker]

If you don't declare the number with a decimal place, it will start to fail at around 1.678*10^7.

Try calling:

IsRational(16778079) - this will be false.
IsRational(16778079.) - this will be true.