This is the case with hashing algorithms in general. The important part is "For two parameters k1 and k2 that are equal, std::hash<Key>()(k1) == std::hash<Key>

This is the case with hashing algorithms in general. The important part is "For two parameters k1 and k2 that are equal, std::hash<Key>()(k1) == std::hash<Key>()(k2)." This is what allows hash maps to work.