Hiding class private member to client using a proxy class

[xgiovio]

main.cpp

#include <iostream>
#include <string>
#include "class_interface.h"

using namespace std;



int main (){
    
    interface obj(1,2); // create an interface object;
    obj.print();    // print memebers data;
    
    
    
    return 0;


} 

class_interface.h

 #ifndef Test_class_interface_h
#define Test_class_interface_h


class implementation;
class interface {
    
public:

    interface (int a = 0, int b = 0);
    void print();

private:
    implementation * ptr;
    
    
};



#endif 

class_interface.cpp

  #include "class_interface.h"
#include <iostream>

using namespace std;


////////////////////////////// implementation

class implementation {
    
    public:
        implementation(int a = 0, int b = 0)
        : var1(a), var2(b)
        {}
    
    
        void print(){
            cout << var1 << endl;
            cout << var2 << endl;
    
        }
    
    private:
    
    const int var1;
    const int var2;

};


/////////////////////////////// interface

interface::interface(int a, int b)
: ptr(new implementation(a,b)){}

void interface::print(){
    ptr->print();

}