如何保存类的成员变量到其他类中_c++一个类的全局变量如何在另一个类赋值且保存-优快云博客

本文链接：https://blog.youkuaiyun.com/DefiniteGoal/article/details/132117409

文章详细介绍了C++中的模板、成员对象指针和类型推断在结构体中的使用，展示了如何检查是否是成员对象指针以及对结构体成员的动态访问和赋值。

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#include <iostream>

struct Point
{
    int x;
    int y;
};

struct MyStruct
{
    int a;
    int b;
    Point point;
};

template<typename T>
struct GetMemberClass{};

template<typename C, typename M>
struct GetMemberClass<M C::*>
{
    using ClassType = C;
    using MemberType = M;
};

template<typename MemberType>
bool is_member_object_pointer(MemberType entity)
{
    return std::is_member_object_pointer<MemberType>::value;
}

int main()
{
    MyStruct obj;
    MyStruct* ptr = &obj;
    obj.a = 5;
    obj.b = 7;
    obj.point.x = 11;
    obj.point.y = 12;

    obj.point = { 21, 22 };
    std::cout << obj.point.x << "," << obj.point.y << std::endl;

    auto TypePointX = &Point::x;

    std::cout << "std::is_member_object_pointer<"
        << typeid(TypePointX).name() << "> = "
        << std::is_member_object_pointer<decltype(TypePointX)>::value << std::endl;

    std::cout << "std::is_member_object_pointer<"
        << typeid(TypePointX).name() << "> = "
        << is_member_object_pointer(&Point::x) << std::endl;

    auto point = &MyStruct::point;
    ((obj.*point).*TypePointX) = 21;

    auto TypeA = &MyStruct::a;
    (obj.*TypeA) = 500;

    int MyStruct::*TypeAA = &MyStruct::a;

    std::cout << typeid(TypeA).name() << std::endl;
    std::cout << obj.*TypeA << std::endl;
    std::cout << obj.*TypeAA << std::endl;
    std::cout << ptr->*TypeA << std::endl;
    std::cout << "Hello World!\n";

    return 0;
}