// each object maintains a pointer 'this' to itself;
// explicit or implicit use of 'this';
// 'this' pointer refers to object members;
// type of 'this' pointer depends on the type of object AND whether the
// member function in which 'this' is used is declared 'const';
// in a non-constant member function of a class A, 'this' pointer has type
// A * const (a constant to an A object);
// in a constant member function of class A, 'this' pointer has type
// A const * const (a constant pointer to a constant A type)

#include <iostream.h>

class test {
public:
    test(int = 0);     // default constructor
    void print() const;
private:
    int x;
};

test::test(int a) {x = a;}          // constructor, add if (x == 0) and run.
                                    // if the class has the constructor, has
                                    // the default constructor been called?
void test::print() const  {         // type of 'this': const * const, see above
    cout << "        x = " << x
    << "\n this->   = " << this->x
    << "\n(*this).x = " << (*this).x << '\n';
}

main( )  {
    test a(12);
    a.print();

    getchar();
    return 0;
}