Operator new

If you are going to implement new operator for your class you need to remember that:
1. new returns void pointer
2. new takes one parameter of type size_t.
Here is an example:

#include <iostream>
using namespace std;

class Test
{
    int x;
    int y;

public:
    Test() : x(100), y(100) 
    {
        cout << "Test constructor" << endl;
    }

    void* operator new(size_t size)
    {
        cout << "Test::operator new" << endl;
        Test* p = (Test*)malloc(size);
        cout << "size is " << size << endl;
        return p;
    }

    void Out()
    {
        cout << "x = " << x << endl;
        cout << "y = " << y << endl;
    }
};


int main()
{
    Test* test2 = new Test;
    test2->Out();
    delete test2;
    return 0;
}

This program will show that new receives the size of the object as the input parameter. This new function was called before the constructor.