Logical XOR operator in C++?

Question

Is there such a thing? It is the first time I encountered a practical need for it, but I don\'t see one listed in Stroustrup. I intend to write:

// Detect wh         


        

Answer 1

Here is how I think you write an XOR comparison in C++:

bool a = true;   // Test by changing to true or false
bool b = false;  // Test by changing to true or false
if (a == !b)     // THIS IS YOUR XOR comparison
{
    // do whatever
}

Proof

XOR TABLE
 a   b  XOR
--- --- ---
 T   T   F
 T   F   T
 F   T   T
 F   F   F

a == !b TABLE
 a   b  !b  a == !b
--- --- --- -------
 T   T   F     F
 T   F   T     T
 F   T   F     T
 F   F   T     F

The proof is that an exhaustive study of inputs and outputs shows that in the two tables, for every input set the result is always the identical in the two tables.

Therefore, the original question being how to write:

return (A==5) ^^ (B==5)

The answer would be

return (A==5) == !(B==5);

Or if you like, write

return !(A==5) == (B==5);