项目3 - 点类派生直线类】定义点类Point,并以点类为基类,派生出直线类Line,从基类中继承的点的信息表示直线的中点。请阅读下面的代码,并将缺少的部分写出来。
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- #include<iostream>
- #include<Cmath>
- using namespace std;
- class Point //定义坐标点类
- {
- public:
- Point():x(0),y(0) {};
- Point(double x0, double y0):x(x0), y(y0) {};
- void PrintPoint(); //输出点的信息
- protected:
- double x,y; //点的横坐标和纵坐标
- };
- void Point::PrintPoint()
- {
- cout<<"Point: ("<<x<<","<<y<<")"; //输出点
- }
- class Line: public Point //利用坐标点类定义直线类, 其基类的数据成员表示直线的中点
- {
- public:
- Line(Point pts, Point pte); //构造函数,用初始化直线的两个端点及由基类数据成员描述的中点
- double Length(); //计算并返回直线的长度
- void PrintLine(); //输出直线的两个端点和直线长度
- private:
- class Point pts,pte; //直线的两个端点,从Point类继承的数据成员表示直线的中点
- };
- int main()
- {
- Point ps(-2,5),pe(7,9);
- Line l(ps,pe);
- cout<<"About the Line: "<<endl;
- l.PrintLine(); //输出直线l的信息:两端点及长度
- cout<<"The middle point of Line is: ";
- l.PrintPoint(); //输出直线l中点的信息
- return 0;
- }
程序运行代码:
/* *Copyright (c)2014,烟台大学计算机与控制工程学院 *All rights reserved. *文件名称:d.cpp *作 者:张旺华 *完成日期:2015年5月31日 *版 本 号:v1.0 */ #include <iostream> #include<iomanip> #include<cstring> #include <cmath> using namespace std; class Point { public: Point(double x=0,double y=0):X(x),Y(y) {} void printPoint(); double getX(); double getY(); protected: double X,Y; }; void Point::printPoint() { cout<<"("<<X<<","<<Y<<")"<<endl; } double Point::getX() { return X; } double Point::getY() { return Y; } class Line :public Point { public: Line(Point P1=(0,0), Point P2=(0,0)):p1(P1),p2(P2), p((P1.getX()+P2.getX())/2,(P1.getY()+P2.getY())/2) {}; double Length(); //求线段长度 void printLine(); //输出线段起始点、终止点,长度 void printPoint(); //输出线段中点坐标 private: Point p1,p2,p; }; void Line::printPoint() { cout<<"("<<p.getX()<<","<<p.getY()<<")"<<endl; } void Line::printLine() { cout<<" 1st "<<endl; p1.printPoint(); cout<<" 2nd "<<endl; p2.printPoint(); cout<<" The Length of Line: "<<Length()<<endl; } double Line::Length() { double dx = p1.getX() - p2.getX(); double dy =p1.getY() - p2.getY(); return sqrt(dx*dx+dy*dy); } int main() { Point ps(-2,5),pe(7,9); Line l(ps,pe); cout<<"About the Line: "<<endl; l.printLine(); //输出直线l的信息 cout<<"The middle point of Line is: "; l.printPoint(); //输出直线l中点的信息 return 0; }
运行结果:
知识点运用及学习心得:
考察构造函数,继承的理解。
时间: 2024-08-06 20:03:33