怎样在C++中使用type traits？

#include <type_traits>
#include <iostream>

template<typename T>
void print_type_info(T value) {
    if constexpr (std::is_integral_v<T>) {
        std::cout << "Integral type: " << value << std::endl;
    } else if constexpr (std::is_floating_point_v<T>) {
        std::cout << "Floating point type: " << value << std::endl;
    } else {
        std::cout << "Other type: " << value << std::endl;
    }
}

int main() {
    print_type_info(42);          // Integral type: 42
    print_type_info(3.14);        // Floating point type: 3.14
    print_type_info("Hello");     // Other type: Hello
    return 0;
}

#include <type_traits>
#include <vector>
#include <iostream>

template<typename T>
void optimize_vector(std::vector<T>& vec) {
    if constexpr (std::is_trivially_copyable_v<T>) {
        // 使用 memcpy 进行优化，因为类型是平凡拷贝的
        T* data = vec.data();
        std::memcpy(data, data, vec.size() * sizeof(T));
        std::cout << "Optimized copy for trivially copyable type." << std::endl;
    } else {
        // 使用普通的拷贝
        std::vector<T> temp = vec;
        vec = std::move(temp);
        std::cout << "Standard copy for non-trivially copyable type." << std::endl;
    }
}

int main() {
    std::vector<int> intVec = {1, 2, 3};
    std::vector<std::string> stringVec = {"a", "b", "c"};

    optimize_vector(intVec);     // Optimized copy for trivially copyable type.
    optimize_vector(stringVec);  // Standard copy for non-trivially copyable type.
    return 0;
}