gistfile1.c++

#include <iostream>

using namespace std;

class A
{
protected:
public:
    int count;
    A() : count(1) { };
    void retain() { ++count; }
    void release() { if (--count == 0) {  delete this; } }
    virtual ~A() { }
    void operator delete(void* ptr, size_t s) {
        A* a = (A *) ptr;
        if (a->count > 1) {
            cout << "Attempt to delete object with retaincount > 1" << endl;
            abort();
        } else {
            ::operator delete(ptr);
        }
    };
};

class B : public A
{
public:
    virtual ~B() { }
};

template<typename T>
class C : public B
{    
public:
    void * operator new(size_t s) {
        return (void *) malloc(s);
    }
    
    void operator delete(void* ptr, size_t s) {        
        A* a = (A *) ptr;
        if (a->count > 1) {
            cout << "Attempt to delete object with retaincount > 1" << endl;
            abort();
        } else {
            free(ptr); /*i.e. strategy*/
        }
    }

    virtual ~C() { /* this could clean up resources! */ }
    
};

int main()
{
    /* DO IT LIKE THIS */
    A* b = new C<int>;
    b->release();
    /* Or like this */
    A* c = new C<int>;
     delete c;
    /* Should work for B too */
    A* e = new B;
    delete e;
    /* But never like this */
    cout << "Fail here" << endl;
    A* d = new C<int>;
    d->retain();
    delete d; 
    
    cout << " here too" << endl;
    B* f = new B;
    f->retain();
    delete f;
    
}