Question

Suppose I have a class:

class test {
public:
   void print();
private:
   int x;
};

void test::print()  
{  
    cout<< this->x;  
}

and I have these variable definitions:

test object1;
test object2;

When I call object1.print() this happens to store address of object1 and so I get x from object1 printed and when I call object2.print() this happens to store address of object2 and I get x from object2 printed. How does it happen?

Answer 1

Each non-static member function has an implicit hidden “current object” parameter that is exposed to you as this pointer.

So you can think that for

test::print();

there’s some

test_print( test* this );

global function and so when you write

objectX.print();

in your code the compiler inserts a call to

test_print(&objectX);

and this way the member function knows the address of “the current” object.