继承与派生

  定义一个point类，派生Rectangle类和Circle类，计算各派生类对象的面积Area().

#include<iostream> 
using namespace std;
class point
{
    protected:
        double x;
        double y;
        public:
            point(double X,double Y):x(X),y(Y)
            {            }
            double getX() const
            {
                 return x;              
            }
            double getY() const
            {
                return y; 
            }    
};
class Rectangle:public point 
{
        protected:
        double longth;
        double width;
        public:
            Rectangle(double X,double Y,double l,double w):point(X,Y),longth(l),width(w){
            }
            double getArea() const
            {
                return longth*width;
            }
};
class Circle:public point
{
    protected:
        double r;
        public:
            Circle(double X,double Y,double R):point(X,Y),r(R){
            }
            double getArea() const
            {
                return (3.14159*r*r);
            }        
};
int main()
{Rectangle A(0,0,5,2);
Circle B(0,0,2);
cout<<"Rectangle area"<<A.getArea()<<endl;
cout<<"Circle area"<<B.getArea()<<endl;
return 0;

设计一个建筑物类Building，由它派生出教学楼TeachBuilding和宿舍楼类DormBuilding，前者包括教学楼编号，层数，教室数，总面积等基本信息，后者包括宿舍楼编号，层数，宿舍数，总面积和容纳学生总人数等基本信息。

 

#include<iostream>
using namespace std;
class Building
{
    protected:
        int number;
        int floor;
        double area;
        public:
            Building(int N,int F,double A):number(N),floor(F),area(A){                
            }
            int getnumber() const{
            return number;}
            int getfloor() const{
            return floor;}
            double getarea() const{
            return area;}
};
class TeachBuilding:public Building{
    private:
        int classroom;
        public:
        TeachBuilding(int N,int F,double A,int R):Building(N,F,A),classroom(R){

        }
        int grtclassroom() const{
        return classroom;}    
};
class DormBuilding:public Building{
    private:
    int dorm;
    int student;
    public:
      DormBuilding(int N,int F,double A,int D,int S):Building(N,F,A),dorm(D),student(S){
      }
      int getdorm() const{
      return  dorm;}
      int getstudent()const{
      return student;}
};
int main()
{
    TeachBuilding O(1,4,34,600);
    DormBuilding E(2,5,23,400,64);
    cout<<"TeachBuilding number="<<O.getnumber()<<" floor="<<O.getfloor()<<" classroom="<<O.grtclassroom()<<" area="<<O.getarea()<<endl;
    cout<<"DormBuilding number="<<E.getnumber()<<" floor="<<E.getfloor()<<" dorm="<<E.getdorm()<<" area="<<E.getarea()<<" student="<<E.getstudent()<<endl;
    return 0;
}