What are some advanced hashing techniques in C++11?

What are some advanced hashing techniques in C++11?

In C++11, you can use unordered_map and custom hash functions. Would you like to know how to implement them?

Yes, please explain how to create a custom hash function.

To create a custom hash function, define a struct with an operator() that takes your key type and returns a size_t hash value.

Can you provide an example of a custom hash function?

Sure! Here's a simple example for a struct called 'Person':

struct Person {
    std::string name;
    int age;
};

struct PersonHash {
    size_t operator()(const Person& p) const {
        return std::hash<std::string>()(p.name) ^ std::hash<int>()(p.age);
    }
};

This combines the hashes of the name and age.

How do I use this custom hash function with unordered_map?

You can use it like this:

std::unordered_map<Person, std::string, PersonHash> personMap;

This allows you to store and retrieve values using your custom Person keys.