Set Query

[Don Wells]

I believe that VBA has a built in boolean function to determine if a given number (from the set 2^0; 2^1; 2^2; ... 2^n), is included in the number returned by the sum of all numbers in the set.

i.e.
    4 tested against 15 would return True
    4 tested against 11 would return False

Can anyone point to documentation on the usability of this function?

T.I.A.

[HansV]

There is no built-in function for that, but you can use the And operator:

Code: Select all

Function TestBit(lngNumber As Long, lngBit As Long) As Boolean
  TestBit = (lngNumber And 2 ^ lngBit = 2 ^ lngBit)
End Function

This uses
15 And 4 = 4
11 And 4 = 0

[StuartR]

Hans,

An extra "Then" has crept into your code, this needs to be deleted for it to compile.

[HansV]

Thanks, that's what you get when you change your mind while posting.

[Don Wells]

Thank you Hans and Stuart