Better way to say x == Foo::A || x == Foo::B || x == Foo::C || …?

Question

Let\'s say I have a bunch of well-known values, like this (but const char * is just an example, it could be more complicated):

const char *A = \"A\"         


        

Answer 1

If you have C++11:

auto res = some_complicated_expression_with_ugly_return_type;
if (res == A
    || res == C
    || res == E
    || res == G) {
}

if not, you can still eliminate the type declaration by using a template function:

template 
bool matches(T t) {
    return t == A || t == C || t == E || t == G;
}

if (matches(some_complicated_expression_with_ugly_return_type)) {
}