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Asked: 2026-05-12T14:57:37+00:00

probably a simple question but I seem to be suffering from programmer’s block. :)

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probably a simple question but I seem to be suffering from programmer’s block. 🙂

I have three boolean values: A, B, and C. I would like to save the state combination as an unsigned tinyint (max 255) into a database and be able to derive the states from the saved integer.
Even though there are only a limited number of combinations, I would like to avoid hard-coding each state combination to a specific value (something like if A=true and B=true has the value 1).

I tried to assign values to the variables so (A=1, B=2, C=3) and then adding, but I can’t differentiate between A and B being true from i.e. only C being true.

I am stumped but pretty sure that it is possible.
Thanks

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1 Answer

  1. Editorial Team

    Binary maths I think. Choose a location that’s a power of 2 (1, 2, 4, 8 etch) then you can use the ‘bitwise and’ operator & to determine the value.
    Say A = 1, B = 2 , C= 4

    00000111 => A B and C => 7

    00000101 => A and C => 5

    00000100 => C => 4

    then to determine them :

    if( val  & 4 ) // same as if (C)
if( val  & 2 ) // same as if (B)
if( val  & 1 ) // same as if (A)

if((val  & 4) && (val & 2)  ) // same as if (C and B)

    No need for a state table.

    Edit: to reflect comment
    If the tinyint has a maximum value of 255 => you have 8 bits to play with and can store 8 boolean values in there

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