#include <iostream>
   
   using namespace std;
   
   // Definition for Class SL
   class SL {
   private: // Each object contains two values
       int *ptr;  // Pointer to int
       int val;   // Just an int
   public: // Member functions
       SL();
       ~SL();
       void Readin();
       void Printout();
       void Erase();
   };
   
   // Constructor for Class SL
   SL::SL()
   {ptr = 0;
    cout << "allocated SL " << this << endl;
   }
   
   SL::~SL()
   {
    cout << "deallocated SL " << this << endl;
    this->Erase();}
   
   void SL::Printout() // Printing out the contents of a SL
   {
      if (ptr == 0) 
         {cout << "data " << " 0 value none int " << val << endl; return;}
      cout << "data " << ptr << " value " << *ptr << " int " << val << endl;
      return;
   }
   
   void SL::Readin()  // Reading in the contents of a SL
   { cout << "Input two values" << endl;
     ptr = new int;
     cin >> *ptr >> val;
   }
   
   void SL::Erase() {
      delete(ptr);
      ptr=0;
   }
   
   int main()
   {
     cout << endl;
   
     SL l;     //   Ae0
     l.Readin();
     cout << "SL l" << " Located at " << &l << endl;
     l.Printout();
     cout << endl;
            //  Ae0    A08   4    3
   
     SL m;     //    Ad0
     m.Readin();
     cout << "SL m"  << " Located at " << &m<< endl;
     m.Printout();
     cout << endl;
            //  Ad0    A18   2    1
   
     SL o(m);   //   Ac0
   //  Terrible copy because the default CC does not
   //  copy the dynamic allocated memeory
     cout << "SL o"  << " Located at " << &o<< endl;
     o.Printout();
     cout << endl;
            //  Ac0    A18   2    1
   
   l.Erase();
   m.Erase();
   
   // One should not use the o list after this point
   //  When we try to delete it it creates a seg fault
   
     cout << "SL l"  << " Located at " << &l<< endl;
     l.Printout();
            //  Ae0    A0     --   3
     cout << "SL m"  << " Located at " << &m<< endl;
     m.Printout();
            //  Ad0    A0    --    1
     cout << "SL o"  << " Located at " << &o<< endl;
     o.Printout();
            //  Ac0    A18   ...2224    1
     cout << endl;
   
     return 0;
   }