How do I customize hashing and equality with std::map?

In C++, the `std::map` is a sorted associative container that contains key-value pairs. When using `std::map`, the default behavior employs the `std::less` comparator for keys and the default equality operator for checking if keys are equivalent. However, in cases where custom behavior is desired—for example, when dealing with complex types or a specific hashing strategy—it's possible to create a custom comparator to customize both hashing and equality operations. Below is an explanation of how to achieve this:

// Define a custom comparator class
struct CustomComparator {
    bool operator()(const std::string& lhs, const std::string& rhs) const {
        // Define your custom comparison logic
        return lhs.length() < rhs.length(); // Compare based on length
    }
};

// Example usage
int main() {
    std::map<:string int customcomparator> customMap;
    customMap["apple"] = 1;
    customMap["banana"] = 2;

    // Accessing the values
    std::cout << customMap["apple"];  // Outputs: 1
    std::cout << customMap["banana"]; // Outputs: 2
}