Comparison operators on booleans trick
boolean, boolean-operations, c++, comparison-operators
Solution
Will the performance increase by this trick?
On any processor where it would have any benefit, when `P` and `Q` are simple variables, this would be simple enough that you should expect compilers to make use of it already without requiring any source code rewriting.
But keep in mind that `P < Q` in general has a distinct disadvantage over `!P && Q`: it requires evaluation of `Q`, when the result is already known if `P` evaluates to `true`. The same applies to all the other relational operators.
Is there any example code using this trick (in any language)?
Not as a trick, but because it arguably leads to code that's easier to understand (not any specific language):
if ((a == null) != (b == null))
throw "a and b must either both be null, or both be non-null";
It could be written with `^`. Which is easier to read is a matter of opinion.
Problem
In C++, the logical operators `&&`, `||`, `!` are there, which corresponds to conjunction , disjunction , negation , respectively. But I noticed the comparison operators `==`, `!=`, `<`, `>`, `<=`, `>=` can be used for booleans as well! Given that `P` and `Q` are booleans: `P == Q` is bicontitional , `P != Q` is exclusive disjunction , `P < Q` is converse nonimplication , `P > Q` is nonimplication , `P <= Q` is implication , And `P >= Q` is converse implication . My questions are: Will the program perform better by this trick? Is there any example code using this trick (in any language)?