lst-0117-book.cpp
// https://godbolt.org/z/cveT8Ej7q
struct EqEntry {
bool operator()(const Entry&a, const Entry&b) const {
return a.city_==b.city_;
}
};
struct HashEntry {
std::hash<string> sHash;
std::hash<int> iHash;
size_t operator()(const Entry& a) const {
return sHash(a.city_) ^ iHash(a.zip_); // (ERR) too many elements
}
};