If statement for multiple scenarios

Question

I am struggling completing this if statement. There must be an easier way to go through all combination because this can't be good practice.

if( one == true && two == true && three == true ...)
else if( one != true && two == true && three == true ...)

I wonder if I want to go through all combinations is there any other way of doing this rather than duplicating the expression?

Answer 1

One way would be converting your one, two, and three values to a single int with the bits properly set, and using a switch statement on binary masks, like this:

int combined=0;
// Construct a binary representation using your Boolean values as bits:
// Value of one goes to bit zero
if (one) combined   |= (1 << 0);
// Value of one goes to bit one
if (two) combined   |= (1 << 1);
// Value of three goes to bit two
if (three) combined |= (1 << 2);
switch (combined) {
case 0: // All false
    break;
case 1: // one is true, other are all false
    break;
...
case 7: // All true
    break;
}

All eight combinations are now encoded as integer values:

int    three two one
_--    ----- --- ---
0    -    0   0   0 
1    -    0   0   1 
2    -    0   1   0 
3    -    0   1   1 
4    -    1   0   0 
5    -    1   0   1 
6    -    1   1   0 
7    -    1   1   1 

It goes without saying that you need to heavily comment code like this for readers of your code who have not memorized binary representations of small numbers.