A multilevel hierarchy : class hierarchy « Class « C++ Tutorial






#include <iostream> 
#include <cstring> 
using namespace std; 
 
class Shape { 
  // private 
  double width; 
  double height; 
public: 
  Shape() { 
    width = height = 0.0; 
  } 
 
  Shape(double w, double h) { 
    width = w; 
    height = h; 
  } 
 
  Shape(double x) { 
    width = height = x; 
  } 
 
  void display() { 
    cout << "Width and height are " << width << " and " << height << "\n"; 
  } 
 
  double getWidth() { return width; } 
  double getHeight() { return height; } 
  void setWidth(double w) { width = w; } 
  void setHeight(double h) { height = h; } 
}; 
 
class Triangle : public Shape { 
  char style[20];
public: 
 
  /* This automatically invokes the default constructor of Shape. */ 
  Triangle() { 
    strcpy(style, "unknown"); 
  } 
 
  Triangle(char *str, double w, double h) : Shape(w, h) { 
    strcpy(style, str); 
  } 
   
  Triangle(double x) : Shape(x) { 
    strcpy(style, "isosceles");  
  } 
 
  double area() { 
    return getWidth() * getHeight() / 2; 
  } 
 
  void showStyle() { 
    cout << "Triangle is " << style << "\n"; 
  } 
}; 
 
class NameTriangle : public Triangle { 
  char name[20]; 
public: 
  NameTriangle(char *clr, char *style, double w, double h) : Triangle(style, w,
 h) { 
    strcpy(name, clr); 
  } 
 
  void displayName() { 
    cout << "Name is " << name << "\n"; 
  } 
}; 
 
int main() { 
  NameTriangle t1("A", "right", 8.0, 12.0); 
  NameTriangle t2("B", "isosceles", 2.0, 2.0); 
 
  t1.showStyle(); 
  t1.display(); 
  t1.displayName(); 
  cout << "Area is " << t1.area() << "\n"; 
 
  t2.showStyle(); 
  t2.display(); 
  t2.displayName(); 
  cout << "Area is " << t2.area() << "\n"; 
 
  return 0; 
}
Triangle is right
Width and height are 8 and 12
Name is A
Area is 48
Triangle is isosceles
Width and height are 2 and 2
Name is B
Area is 2








9.7.class hierarchy
9.7.1.A simple class hierarchy.
9.7.2.A multilevel hierarchy
9.7.3.Deriving ADTs from other ADTs
9.7.4.Use typeid to test type equality
9.7.5.Multiple base class constructing and destructing
9.7.6.Three level inheritance
9.7.7.Overload across class hiearchy
9.7.8.Shadow base class function in its two children classes
9.7.9.Reference another class in member function
9.7.10.Shadow function with the same name in base class
9.7.11.Inherit protected fields
9.7.12.Call constructor from base class