Create a variable to hold objects of different types C++

Question

I have 3 different objects A, B and C. Depending on the the parameter given, I would like to choose among these different objects. In

Answer 1

It seems to me that you should use a virtual common base class/struct and a pointer to this base class/struct.

The following is a full working example

#include 

struct Base
 { virtual void printHello () = 0; };

class A : public Base { 
  public: 
    void printHello() { std::cout << "HELLO A" << std::endl; }
}; 

class B  : public Base{ 
  public: 
    void printHello() { std::cout << "HELLO B" << std::endl; }  
};

class C  : public Base{ 
   public: 
     void printHello() { std::cout << "HELLO C" << std::endl; }  
}; 

int main () { 
    std::string key = "c"; 
    A a; 
    B b; 
    C c; 
    Base * obj; 

    if (key == "a") obj = &a; 
    else if (key == "b") obj = &b; 
    else obj = &c;
    obj->printHello(); // print Hello C.
    return 0; 
}