// 10. Наследяване на класове. Базови и производни класове.
//     Защитени членове на клас.
//
// Fig. 9.17: point3.h
// Point3 class definition represents an x-y coordinate pair.
#ifndef POINT3_H
#define POINT3_H

class Point3 {
public:
   Point3( int = 0, int = 0 ); // default constructor

   void setX( int );    // set x in coordinate pair
   int getX() const;    // return x from coordinate pair  
   void setY( int );    // set y in coordinate pair
   int getY() const;    // return y from coordinate pair  
   void print() const;  // output Point3 object
private:                // or protected:
   int x;  // x part of coordinate pair
   int y;  // y part of coordinate pair
}; // end class Point3

#endif
/****/

// Fig. 9.18: point3.cpp
// Point class member-function definitions.
#include <iostream>  
using std::cout;
#include "point3.h"   // Point3 class definition

// default constructor
Point3::Point3( int xValue, int yValue )
   : x( xValue ), y( yValue )
{  } // end Point3 constructor

// set x in coordinate pair
void Point3::setX( int xValue )
{  x = xValue; // no need for validation
} // end function setX

// return x from coordinate pair
int Point3::getX() const
{  return x;
} // end function getX

// set y in coordinate pair
void Point3::setY( int yValue )
{  y = yValue; // no need for validation
} // end function setY

// return y from coordinate pair
int Point3::getY() const
{  return y;
} // end function getY
   
// output Point3 object
void Point3::print() const
{  cout << '[' << getX() << ", " << getY() << ']';
} // end function print
/****/

// Fig. 9.19: circle4.h
// Circle4 class contains x-y coordinate pair and radius.
#ifndef CIRCLE4_H
#define CIRCLE4_H

#include "point3.h"  // Point3 class definition

class Circle4 : public Point3 {
public:
   // default constructor
   Circle4( int = 0, int = 0, double = 0.0 );  

   void setRadius( double );   // set radius
   double getRadius() const;   // return radius

   double getDiameter() const;       // return diameter
   double getCircumference() const;  // return circumference
   double getArea() const;           // return area
   void print() const;         // output Circle4 object
private: 
   double radius;  // Circle4's radius
}; // end class Circle4
#endif 
/****/

// Fig. 9.20: circle4.cpp
// Circle4 class member-function definitions.
#include <iostream>  
using std::cout;
#include "circle4.h"   // Circle4 class definition

// default constructor
Circle4::Circle4( int xValue, int yValue, double radiusValue )
   : Point3( xValue, yValue )  // call base-class constructor
{  setRadius( radiusValue );
} // end Circle4 constructor

// set radius 
void Circle4::setRadius( double radiusValue )
{  radius = ( radiusValue < 0.0 ? 0.0 : radiusValue );
} // end function setRadius

// return radius 
double Circle4::getRadius() const
{  return radius;
} // end function getRadius

// calculate and return diameter
double Circle4::getDiameter() const
{  return 2 * getRadius();
} // end function getDiameter

// calculate and return circumference
double Circle4::getCircumference() const
{  return 3.14159 * getDiameter();
} // end function getCircumference

// calculate and return area
double Circle4::getArea() const
{  return 3.14159 * getRadius() * getRadius();
} // end function getArea

// output Circle4 object
void Circle4::print() const
{  cout << "Center = ";
   Point3::print();      // invoke Point3's print function
   cout << "; Radius = " << getRadius();
} // end function print
/*****/

// Fig. 9.21: circletest4.cpp
// Testing class Circle4.
#include <iostream>  
using std::cout;
using std::endl;
using std::fixed;

#include <iomanip>
using std::setprecision;

#include "circle4.h"  // Circle4 class definition

int main()
{  Circle4 circle( 37, 43, 2.5 ); // instantiate Circle4 object

   // display point coordinates
   cout << "X coordinate is " << circle.getX() 
        << "\nY coordinate is " << circle.getY()
        << "\nRadius is " << circle.getRadius();
   circle.setX( 2 );          // set new x-coordinate
   circle.setY( 2 );          // set new y-coordinate
   circle.setRadius( 4.25 );  // set new radius

   // display new circle value
   cout << "\n\nThe new location and radius of circle are\n";
   circle.print();

   // display floating-point values with 2 digits of precision
   cout << fixed << setprecision( 2 );

   // display Circle4's diameter
   cout << "\nDiameter is " << circle.getDiameter();

   // display Circle4's circumference
   cout << "\nCircumference is " << circle.getCircumference();

   // display Circle4's area
   cout << "\nArea is " << circle.getArea();
   cout << endl;

   return 0;  // indicates successful termination 
} // end main