determine if an integer value is odd or is even

[RemiD]

needed this today, and i knew that i had the functions on my harddrive, somewhere :

Code: [Select]

;determine if an integer value is odd or is even 20160101
Graphics3D(640,480,32,2)

SeedRnd(MilliSecs())

For i% = 0 To 101
 R1% = IsOdd(i)
 R2% = IsEven(i)
 DebugLog("i = "+i)
 DebugLog("IsOdd ? "+R1)
 DebugLog("IsEven ? "+R2)
 WaitKey()
Next

End()

Function IsOdd(TInt%)
 R% = Abs(TInt) Mod 2
 If(R = 0)
  Return False
 ElseIf(R = 1)
  Return True
 EndIf
End Function

Function IsEven(TInt%)
 R% = Abs(TInt) Mod 2
 If(R = 0)
  Return True
 ElseIf(R = 1)
  Return False
 EndIf
End Function


[Steve Elliott]

I always think it's tidier/less code to not use else in cases when there are only 2 possibilities.

Code: [Select]

Function IsOdd(TInt%)
 R% = Abs(TInt) Mod 2

 If(R = 0)
  Return False
 Endif

 Return True
End Function


[STEVIE G]

Why not use one simple function ... if it isn't even it's odd. 

Code: [Select]

Function IsEven( I% )

Return ( Abs(I) Mod 2 ) = 0

End Function


[Steve Elliott]

Yes you could re-write it completely, simplify even more and use a not if required.

Code: [Select]

If( Not IsEven( num ) )  ; odd number


[TomToad]

If number & 1
    Number is odd
Else
    Number is even

[STEVIE G]

If number & 1
    Number is odd
Else
    Number is even

  I knew there must be a bit shift variant.

[Steve Elliott]

Haha, nice one.  I love these little efficiencies.   

[RemiD]

i think that you should spend less time trying to optimize a procedure which is already fast enough (it takes 0.00012 millisecond so 0.12 microsecond to complete the procedure on my 8 years old, low end, laptop)

[Steve Elliott]

a) I think you should be grateful for some neat advice and not instead sulk.  And b) that's a lazy attitude to coding, these little efficiencies all add-up.  No excuse for ugly bloaty routines when you were given some good advice, and like you mentioned you can store and re-use them again.

Thanks guys, I for one enjoyed your input.

[GfK]

Code: [Select]

Function IsOdd(num%)
  Return (num & 1)
End Function

Code: [Select]

Function IsEven(num%)
  Return Not (num & 1)
End Function
...or something like that.  Don't use Blitzwhateverstrainthisis any more.

[RemiD]

thanks for teaching me how to behave and programming "Steve Elliott", i feel better now. i am really grateful to you.

[Steve Elliott]

lol personally I love to learn.  If somebody comes up with a better solution than myself I love that!  Because I've learnt something extra...Rather than tell people they are wasting their time and now come up with a sarcastic remark.

[RemiD]

@steve elliott>>you are too smart for me, i give up

[TomToad]

Code: [Select]

Function isEven(num%)
If num Shr 1 Shl 1 = num Then Return True
Return False
End Function

Function isOdd(num%)
If num Shr 1 Shl 1 <> num Then Return True
Return False
End Function
For i = 0 To 100
If isEven(i)
Print i+" is even"
ElseIf isOdd(i)
Print i+" is odd"
Else
Print i+" is nothing"
EndIf
Next


Code: [Select]

Function isEven(num%)
If ((num - 1) Xor num) <> 1 Then Return True
Return False
End Function

Function isOdd(num%)
If ((num - 1) Xor num) = 1 Then Return True
Return False
End Function


Code: [Select]

Function isEven(num%)
For i = -2147483648 To +2147483647 Step 2
If num = i Then Return True
Next
Return False
End Function

Function isOdd(num%)
For i = -2147483647 To +2147483647 Step 2
If num = i Then Return True
Next
Return False
End Function


[Derron]

Code: [Select]

Function isEven(num%)
For i = -2147483648 To +2147483647 Step 2
If num = i Then Return True
Next
Return False
End Function

Function isOdd(num%)
For i = -2147483647 To +2147483647 Step 2
If num = i Then Return True
Next
Return False
End Function


Ohh no ... seems to contain a mistake. Else I would prefer these functions as I see they check all potential candidates. Thanks for the laugh


bye
Ron