Can I add member variables to a structure, after i have declared it?

Question

Can I add member variables to a structure, after i have declared it? For example:

struct address 
    { 
       char name[50]; 
       char street[100]; 
    };

Can i dynamically (through code), add another member variable to the structure? Using something like address.addMember(pinCode); if something like this exists!

struct address 
    { 
       char name[50]; 
       char street[100]; 
       int  pinCode;
    };

Answer 1

What you strive to achieve is not possible so bluntly, however it's not impossible!

One way would be by extending the address by the new members via inheritance.

struct address 
{ 
   char name[50]; 
   char street[100]; 
};

struct pin_address : public address 
{ 
   int pinCode;
};

Other would be by implementing some kind of std::variant - std::map structure which will allow you to dynamically add/remove members.

#include <variant>
#include <map>

using Object = std::variant<int,double,std::string>;
using Members = std::map<std::string,Object>;

struct address
{
    Members m_members;

    address()
    {
        m_members.emplace("name", Object{});
        m_members.emplace("street", Object{});
        m_members.emplace("pinCode", Object{});
    }
}