What are hash templates in C++11?

Can you explain what hash templates are in C++11?

Sure! Hash templates in C++11 allow you to create custom hash functions for user-defined types, enabling their use in hash-based containers.

How do I implement a hash function for my custom class?

You can implement a hash function by defining a struct that overloads the operator() to compute the hash value based on your class's attributes.

Can you give me a code example?

Certainly! Here's a simple example:

struct MyClass {
    int x;
    int y;
};

struct MyClassHash {
    std::size_t operator()(const MyClass& obj) const {
        return std::hash<int>()(obj.x) ^ std::hash<int>()(obj.y);
    }
};

This defines a hash function for MyClass.

What about using hash tables with these templates?

You can use std::unordered_map with your custom hash function by specifying it as a template argument, like this:

std::unordered_map<MyClass, ValueType, MyClassHash> myMap;