Implementation of the code pointed out in http://belkadan.com/blog/2018/03/My-Little-Optimization/. I wasn't aware that template <int... N>(&...name)[N] worked

inset.cpp

#include <iostream>
#include <string_view>

template <size_t... N>
bool isInSet(const std::string_view s, const char (&...S)[N]) {
    return (operator==(s,S) || ...);
}


int main(int argc, char * argv[]) {
    if(argc < 1) {
        return 1;
    }
    std::string str = argv[1];
    bool str_in = isInSet(str,"Battler", "George", "Jessica", "Maria", "Beatrice");
    std::cout << "is " << str 
              << " in set? " << (str_in?"Yes":"No") 
              << std::endl;
        return 0;
}