Inheritance

Inheritance is the process by which one object acquires the properties of another object. This is important because it supports the concept of hierarchical classification.

• Process of deriving new classes based on existing proven classes.
• It allows the programmer to use existing classes as a base for the development of new ones. Which have common features with those that have already been developed.
• The already developed classes are called “super classes” or “base classes”, the classes which inherits the properties are called “child classes”.
• Software reusability is possible through inheritance

Example
class Point
{
public:
 Point ();
 Point(double xval, double yval);
void move (double dx, double dy);
double getX() const;
double getY () const;
private:
      double x;
double y;
};

class Point3D: public Point {

    int _z;

  public:

    Point3D() {

      setX(0);

      setY(0);

      _z = 0;

    }

    Point3D(const int x, const int y, const int z) {

               setX(x);

               setY(y);

               _z = z;

    }

    ~Point3D() { /* Nothing to do */ }

    int getZ() { return _z; }

    void setZ(const int val) { _z = val; }

  };