#include "iostream.h" // This program illustrates the use of nesting one class inside another class mail_info { private: int shipper; int postage; public: void set(int in_class, int in_postage) {shipper = in_class; postage = in_postage; } int get_postage(void) {return postage;} }; class box { private: int length; int width; mail_info label; public: void set(int l, int w, int s, int p) { length = l; width = w; label.set(s, p); } int get_area(void) {return length * width;} }; main() { box small, medium, large; small.set(2, 4, 1, 35); medium.set(5, 6, 2, 72); large.set(8, 10, 4, 98); cout << "The area is " << small.get_area() << "\n"; cout << "The area is " << medium.get_area() << "\n"; cout << "The area is " << large.get_area() << "\n"; } // Result of Execution // // The area is 8 // The area is 30 // The area is 80