#include <iostream>
#include <cmath>
using namespace std;
class Point
{
public:
Point(double x=0,double y=0);
void setPoint(double,double);
double getx()
{
return x;
}
double gety()
{
return y;
}
void display();
protected:
double x,y;
};
class Circle:public Point
{
public:
Circle(double x=0,double y=0,double R=0);
void setR(double,double,double);//半径
double getR()
{
return R;
}
double areas();//圆面积
protected:
double R;
};
Point::Point(double a,double b)
{
x=a;
y=b;
}
void Point::setPoint(double a,double b)
{
x=a;
y=b;
}
void Point::display()
{
cout<<"( "<<getx()<<","<<gety()<<")"<<endl;
}
Circle::Circle(double a,double b,double r):Point(a,b),R(r) {}
void Circle::setR(double a,double b,double r)
{
x=a;
y=b;
R=r;
}
double Circle::areas()
{
return 3.14*R*R;
}
int main()
{
Point p1(3,3),p2(8,8);
Circle c(2,2,4);
cout<<"第一点";
p1.display();
cout<<"第二点";
p2.display();
cout<<"原点为："<<"( "<<c.getx()<<","<<c.gety()<<")"<<" 半径为："<<c.getR()<<" 的圆的面积为："<<c.areas()<<endl;
return 0;
}
感悟：大晚上的在宿舍编程序也不错啊！