Question

In problems like this,

If I were solving a problem in C using recursion where I’d have to find all TRUE or FALSE values for X1, X2 AND X3 satisfying the expression, how would I compare the alignment (whether or not a variable is NOT like X2 in the first clause)against actual true and false values? I could use 0 and 1 and recursively try all permutations, but I’m unsure how to actually go about computing this.

Answer 1

I’m not entirely sure about your question, but you have 4 boolean values which can be represented by 4 bits. By exploiting the internal respresentation for integrals, you can make that in a for loop to check for all possible combinations:

for( int i = 0; i < 16; ++i ) // That's 2^4
{
    int x1 = i & 1;
    int x2 = i & 2;
    int x3 = i & 4;
    int x4 = i & 8;

    if( ( x1 || !x2 || !x3 ) && ( x1 || x2 || x4 ) )
        ... the expression holds for this combination, store it somewhere ...
}