#include <iostream>
    #include <cstdlib>
    using namespace std;
    class OperatorX 
    {
        public:
        void* operator new(size_t sz) throw (const char*)
        {
            void* ptr1 = malloc(sz);
            if (ptr1 == 0) 
                throw "malloc() failed";
            return ptr1;
        }
        void operator delete(void* ptr1) 
        {
            cout << "Operator X :: delete(void*)" << endl;
            free(ptr1);
        } 
    };
    class OperatorY 
    {
        int filler[150];
        public:
        void operator delete(void* ptr1, size_t sz) throw (const char*)
        {
            cout << "Freeing " << sz << " bytes" << endl;
            free(ptr1);
        };
    };
    int main() 
    {
        OperatorX* ptr1 = new OperatorX;
        delete ptr1;
        OperatorY* ptr2 = new OperatorY;
        delete ptr2;
    }

#include <iostream>
    #include <new>
    using namespace std;
    struct N 
    {
        virtual ~N() {  };
        void operator delete(void* ptr1) 
        {
            cout << "N :: operator delete" << endl;
        }
    };
    struct M : N 
    {
        void operator delete(void* ptr1) 
        {
            cout << "M :: operator delete" << endl;
        }
    };
    int main() 
    {
        N* ptr2 = new M;
        delete ptr2;
    }

#include <iostream>
    using namespace std;
    struct OperatorA
    {
        virtual ~OperatorA()
        { 
            cout << "~OperatorA()" << endl; 
        }
        void operator delete[](void* p, size_t)
        {
            cout << "Operator A :: deleteed" << endl;
            delete [] p;
        }
    };
    struct OperatorB : OperatorA 
    {
        void operator delete[](void* p, size_t) 
        {
            cout << "Operator B :: operator deleteed" << endl;
            delete [] p;
        }
    };
    int main() 
    {
        OperatorA* ptr = new OperatorB[2];
        delete[] ptr;
    };

#include <iostream>
    #include <new>
    #include <cstdlib>
    using namespace std;
    const int bsize = 128;
    int *ptr1;
    bool allocate = true;
    void get_memory() 
    {
        cerr << "free store exhausted" << endl;
        delete [] ptr1;
        allocate = false;
    }
    void eat_memory(int size) 
    {
        int *ptr2 = new int[size];
        if (allocate)
            eat_memory(size);
        else
            cerr << "free store addr = " << ptr2 << endl;
    }
    int main()
    {
        set_new_handler(get_memory);
        ptr1 = new int[bsize];
        cerr << "free store addr = " << ptr1 << endl;
        eat_memory(bsize);
        return 0;
    }