Pointers to Derived Types : pointer « Pointer « C++ Tutorial

#include <iostream>
using namespace std;
   
class base {
  int i;
public:
  void set_i(int num) { i=num; }
  int get_i() { return i; }
};
class derived: public base {
  int j;
public:
  void set_j(int num) { j=num; }
  int get_j() { return j; }
};
   
int main()
{
  base *bp;
  derived d;
   
  bp = &d; // base pointer points to derived object
   
  // access derived object using base pointer
  bp->set_i(10);
  cout << bp->get_i() << " ";
   
  return 0;
}

11.1.pointer
	11.1.1.	What is stored in a pointer.
	11.1.2.	Allocating and deleting a pointer
	11.1.3.	Finding Out What Is Stored in Pointers
	11.1.4.	Manipulating Data by Using Pointers
	11.1.5.	Using a pointer to print the contents of the array
	11.1.6.	C++ program shows the use of pointers when accessing structure information from a function.
	11.1.7.	Pointers to Derived Types
	11.1.8.	Manually create a call-by-reference using a pointer.