C++ examples for Class:Inheritance
Defining and using a derived class
#include <iostream> #include <string> // For the string class #include <iostream> #include <iomanip> class Pool// w w w . j a v a 2 s .co m { private: double length {1.0}; double width {1.0}; double height {1.0}; public: // Constructors Pool(double lv, double wv, double hv) : length {lv}, width {wv}, height {hv} {} Pool() = default; // No-arg constructor double volume() const // Function to calculate the volume { return length*width*height; } // Accessors double getLength() const { return length; } double getWidth() const { return width; } double getHeight() const { return height; } friend std::ostream& operator<<(std::ostream& stream, const Pool& pool); }; // Stream output for Pool objects inline std::ostream& operator<<(std::ostream& stream, const Pool& pool) { stream << " Pool(" << std::setw(2) << pool.length << "," << std::setw(2) << pool.width << "," << std::setw(2) << pool.height << ")"; return stream; } using std::string; class Carton : public Pool { private: string material; public: Carton(const string desc = "Cardboard") : material {desc}{} // Constructor // double carton_volume() { return length*width*height; } // Uncomment for an error! }; int main() { // Create a Pool object and two Carton objects Pool pool {40.0, 30.0, 20.0}; Carton carton; Carton candyCarton {"Thin cardboard"}; // Check them out - sizes first of all std::cout << "pool occupies " << sizeof pool << " bytes" << std::endl; std::cout << "carton occupies " << sizeof carton << " bytes" << std::endl; std::cout << "candyCarton occupies " << sizeof candyCarton << " bytes" << std::endl; // Now volumes... std::cout << "pool volume is " << pool.volume() << std::endl; std::cout << "carton volume is " << carton.volume() << std::endl; std::cout << "candyCarton volume is " << candyCarton.volume() << std::endl; std::cout << "candyCarton length is " << candyCarton.getLength() << std::endl; // Uncomment any of the following for an error... // pool.length = 10.0; // candyCarton.length = 10.0; }