Structure and Union C++

Question

I hope you're doing well. I'm presently learning C++ and have been delving into structures and unions. However, I've run into a number of problems and difficulties when working with these principles, and I'm in need of some help to overcome them.

Here is a piece of the code I've been battling with:

#include <iostream>

struct MyStruct {
    int x;
    char y;
};

union MyUnion {
    int x;
    char y;
};

int main() {
    MyStruct s;
    s.x = 10;
    s.y = 'A';

    std::cout << "x: " << s.x << ", y: " << s.y << std::endl;

    MyUnion u;
    u.x = 10;
    std::cout << "x: " << u.x << ", y: " << u.y << std::endl;

    return 0;
}
 

In this code sample, I have discovered four difficulties that I am attempting to resolve:

1.When I attempted to print the value of the x member of the structure MyStruct, I received an error stating "use of undefined type 'MyStruct'". How can I fix this mistake so that I may access and publish the values of structure members?

2.When I tried to assign a value to the x member of the structure MyStruct, I got an error that said "cannot assign to non-static data member within const member function". How can I fix this problem so that I may give values to structure members as needed?

3.When I tried to assign a value to the x member of the union MyUnion, I received the error "member 'x' in union 'MyUnion' is anonymous". How can I fix this problem so that I may assign values to union members as needed?

4.Finally, I am confused how to use unions in this scenario. How can I use unions to effectively store many types of data while ensuring accurate value retrieval and interpretation?

I would be grateful for any insights or advice you can offer to assist me handle these challenges and improve my grasp of C++ structures and unions. Thank you for your help.