//7. Proxy êëàñîâå.
//
// Fig. 7.10: implementation.h
// Header file for class Implementation

class Implementation {
   public:
      Implementation( int v ) { value = v; }
      void setValue( int v ) { value = v; }
      int getValue() const { return value; }

   private:
      int value;
};
-------------------------
// Fig. 7.10: interface.h
// Header file for interface.cpp
class Implementation;   // forward class declaration

class Interface {
   public:
      Interface( int );
      void setValue( int );  // same public interface as
      int getValue() const;  // class Implementation
   private:
      Implementation *ptr;   // requires previous 
                             // forward declaration
};
---------------------------
// Fig. 7.10: interface.cpp
// Definition of class Interface
#include "interface.h"
#include "implementation.h"

Interface::Interface( int v ) 
   : ptr ( new Implementation( v ) ) { }

// call Implementation's setValue function
void Interface::setValue( int v ) { ptr->setValue( v ); }

// call Implementation's getValue function
int Interface::getValue() const { return ptr->getValue(); }
--------------------------
// Fig. 7.10: fig07_10.cpp
// Hiding a class’s private data with a proxy class.
#include <iostream.h>
#include "interface.h"

int main()
{
   Interface i( 5 );
 
   cout << "Interface contains: " << i.getValue() 
        << " before setValue" << endl;
   i.setValue( 10 );
   cout << "Interface contains: " << i.getValue() 
        << " after setValue" << endl;
   return 0;
}
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