Bits of integer

[mfleming]

Just for fun, in APL

Code:


    numbits←{⍺←32 ⋄ ⌈/⍸⌽(⍺⍴2)⊤⍵}

    numbits 25
5
    64 numbits 2*32
33

LHS - Bit width of word holding binary equivalent of RHS value (default 32)

Expression evaluates right to left, modified by parentheses
Expression reads left to right:
Find the largest number in the vector indices of ones in the reversed binary representation of a RHS value. (The number of bits will the the index (OPTON BASE 1) of the one that's furthest to the right in the reversed binary vector of ones and zeros.)

We can use the commute operator to rid ourselves of the parentheses

Code:


    numbits2←{⍺←32 ⋄ ⌈/⍸⌽⍵⊤⍨⍺⍴2}

    128 numbits2 2*63
64

Fourteen characters, not counting spaces and braces
~Mark