C++的一些问题

//重载运算符new与delete
#include<iostream.h>
#include<malloc.h>
class Rect
{
    int length,width;
public:
    Rect(int l,int w)
    {
        length=l;width=w;
    }
    void disp()
    {
        cout<<"面积"<<length*width<<endl;
    }
    void *operator new(size_t size)//重载new运算符成员函数
    {
        cout<<"重载new运算符分配内存"<<endl;
        return malloc(size);
    }
    void operator delete(void *p)//重载delete运算符成员函数
    {
        free(p);
        cout<<"重载delete运算符释放内存"<<endl;
        
    }
};
void main()
{
    Rect *p;
    p=new Rect(5,9);
    p->disp ();
    delete p;
}