// Phil Ottewell's STL Course - http://www.pottsoft.com/home/stl/stl.htmlx
//
// RefCount supp. example          © Phil Ottewell 1997 <philXZY@pottsoftXZY_REMOVEXYZ.com>
//
// Purpose:
//         Shows how copy assignment and copy constructors work with containers

#include <vector>
#include <iostream>

#ifdef _WIN32
using namespace std;
#endif

class MyClass {
public:
    MyClass()
    {
      piRefcount = new int;
      *piRefcount = 1;
      cout << "MyClass Constructor. Refcount = " 
           << dec << *piRefcount << " for pointer " << hex << piRefcount
           << " this = " << this << endl;
    }

    // Copy constructor
    MyClass( const MyClass &mc )
    {
      // Don't use the Copy Assignment in here !
      this->piRefcount = mc.piRefcount;
      ++*piRefcount;
      cout << "MyClass Copy Constructor. Refcount = "
           << dec << *piRefcount << " pointer " << hex << piRefcount
           << " this = " << this << endl;
    }

    // Copy assignment
    MyClass & operator =( const MyClass &mcRHS )
    {
      // Avoid self-assignment
      if ( this != &mcRHS ) {
        cout << "MyClass Copy Assignment. Refcount = "
             << dec << *piRefcount << " before re-assignment for pointer "
             << hex << piRefcount
             << " this = " << this << endl;
        if ( 0 == --*piRefcount ) {
          // If noone else is referencing current value of LHS before
          // assignment it can safely be destroyed
           cout << "MyClass Copy Assignment. deleted pointer"
           << endl;
           delete piRefcount;
        }
        // Copy RHS top LHS
        this->piRefcount = mcRHS.piRefcount;
        // Increase reference count
        ++*piRefcount;
      }
      cout << "MyClass Copy Assignment. Refcount = "
           << dec << *piRefcount << " pointer " << hex << piRefcount
           << " this = " << this << endl;
      return( *this );
    }
     
    ~MyClass()
    {
      if ( piRefcount ) {
        if ( 0 == --*piRefcount ) {
          // Can destroy object's sub parts if no more references
          delete piRefcount;
          piRefcount = NULL;
          cout << "MyClass Destructor. Deleted "
               << "pointer data for pointer " << hex << piRefcount
               << " this = " << this << " because it had 0 references" << endl;
        } else {
          cout << "MyClass Destructor. Refcount = "
               << dec << *piRefcount << " pointer " << hex << piRefcount
               << " this = " << this << " after decr." << endl;
        }
      } else {
        cout << "MyClass Destructor. "
             << "Pointer data already deleted for pointer @ " << hex
             << piRefcount << " this = " << this << endl;
      }
    }
private:
    int *piRefcount;
};

int main() {
   int j;
   MyClass  myTemp;
   vector<MyClass> v;
   vector<MyClass>::iterator iv;

// initialize the vector with values
   cout << "Add some myTemps to vector ..." << endl;
   for ( j = 0; j < 3; j++) {
     v.push_back( myTemp );
   }
   cout << "Erase myTemps from vector ..." << endl;
   while ( ( iv = v.begin() ) != v.end() ) {
     v.erase( iv++ );
   }

   cout << "End of program - destructors should come soon ..." << endl;
   return 0;
}