如何在C++0x中组合哈希值？

#include <iostream>
#include <functional>

int main() {
    std::hash<int> hasher_int;
    std::hash<std::string> hasher_string;

    int hash1 = hasher_int(42);
    std::string str = "hello";
    size_t hash2 = hasher_string(str);

    // 组合哈希值
    size_t combined_hash = hash1 ^ (hash2 + 0x9e3779b9 + (hash1 << 6) + (hash1 >> 2));

    std::cout << "Combined hash: " << combined_hash << std::endl;
    return 0;
}

#include <iostream>
#include <boost/functional/hash.hpp>

int main() {
    boost::hash<int> hasher_int;
    boost::hash<std::string> hasher_string;

    int hash1 = hasher_int(42);
    std::string str = "hello";
    size_t hash2 = hasher_string(str);

    // 组合哈希值
    size_t combined_hash = boost::hash_combine(hash1, hash2);

    std::cout << "Combined hash: " << combined_hash << std::endl;
    return 0;
}

#include <iostream>
#include <string>

size_t custom_hash_combine(size_t seed, size_t hash) {
    seed ^= hash + 0x9e3779b9 + (seed << 6) + (seed >> 2);
    return seed;
}

int main() {
    size_t hash1 = 42;
    std::string str = "hello";
    size_t hash2 = std::hash<std::string>{}(str);

    // 组合哈希值
    size_t combined_hash = custom_hash_combine(hash1, hash2);

    std::cout << "Combined hash: " << combined_hash << std::endl;
    return 0;
}