Problem E: 平面上的点和线——Point类、Line类 (V)
Description
在数学上，平面直角坐标系上的点用X轴和Y轴上的两个坐标值唯一确定，两点确定一条线段。现在我们封装一个“Point类”和“Line类”来实现平面上的点的操作。
根据“append.cc”，完成Point类和Line类的构造方法和show()方法，输出各Line对象和Point对象的构造和析构次序。
接口描述：
Point::show()方法：按格式输出Point对象。
Line::show()方法：按格式输出Line对象。
Line::SetLine(double, double, double, double)方法：设置Line对象起点的x,y坐标（第一个和第二参数）和终点的x,y坐标（第三个和第四个坐标），并返回本对象
Line::SetLine(const Point &, const Point &)方法：设置Line对象的起点（第一个参数）和终点（第二个坐标），并返回本对象
Line::SetLine(const Line&)方法：设置Line对象，复制参数的坐标，并返回本对象
Line::readLine()方法：从标准输入上读入坐标，格式见Sample
Input
输入的第一行为N，表示后面有N行测试样例。
每行为两组坐标“x,y”，分别表示线段起点和终点的x坐标和y坐标，两组坐标间用一个空格分开，x和y的值都在double数据范围内。
Output
输出为多行，每行为一条线段，起点坐标在前终点坐标在后，每个点的X坐标在前，Y坐标在后，Y坐标前面多输出一个空格，用括号包裹起来。输出格式见sample。
C语言的输入输出被禁用。
Sample Input
4 0,0 1,1 1,1 2,3 2,3 4,5 0,1 1,0
Sample Output
Point : (1, -2) is created. Point : (2, -1) is created. Point : (0, 0) is created. Point : (0, 0) Point : (0, 0) is created. Point : (0, 0) is created. Line : (0, 0) to (0, 0) is created. Point : (0, 0) is created. Point : (0, 0) is created. Line : (0, 0) to (0, 0) is created. Point : (0, 0) is created. Point : (0, 0) is created. Line : (0, 0) to (0, 0) is created. Point : (0, 0) is created. Point : (0, 0) is created. Line : (0, 0) to (0, 0) is created. Line : (0, 0) to (1, 1) Line : (1, 1) to (2, 3) Line : (2, 3) to (4, 5) Line : (0, 1) to (1, 0) Point : (1, -2) is copied. Point : (2, -1) is copied. Line : (1, -2) to (2, -1) is created. Point : (1, -2) is copied. Point : (0, 0) is copied. Line : (1, -2) to (0, 0) is created. Point : (2, -1) is copied. Point : (0, 0) is copied. Line : (2, -1) to (0, 0) is created. Point : (1, -2) is copied. Point : (2, -1) is copied. Line : (1, -2) to (2, -1) is copied. Line : (1, -2) to (2, -1) Line : (1, -2) to (2, -1) Line : (2, -1) to (0, 0) Line : (0, 0) to (2, -1) Line : (0, 0) to (2, -1) is erased. Point : (2, -1) is erased. Point : (0, 0) is erased. Line : (2, -1) to (0, 0) is erased. Point : (0, 0) is erased. Point : (2, -1) is erased. Line : (1, -2) to (2, -1) is erased. Point : (2, -1) is erased. Point : (1, -2) is erased. Line : (1, -2) to (2, -1) is erased. Point : (2, -1) is erased. Point : (1, -2) is erased. Line : (0, 1) to (1, 0) is erased. Point : (1, 0) is erased. Point : (0, 1) is erased. Line : (2, 3) to (4, 5) is erased. Point : (4, 5) is erased. Point : (2, 3) is erased. Line : (1, 1) to (2, 3) is erased. Point : (2, 3) is erased. Point : (1, 1) is erased. Line : (0, 0) to (1, 1) is erased. Point : (1, 1) is erased. Point : (0, 0) is erased. Point : (0, 0) is erased. Point : (2, -1) is erased. Point : (1, -2) is erased.
HINT
Append Code
int main(){ int num, i; Point p(1, -2), q(2, -1), t; t.show(); std::cin>>num; Line line[num]; for(i = 0; i < num; i++) { line[i].readLine(); line[i].show(); } Line l1(p, q), l2(p,t), l3(q,t), l4(l1); l1.show(); l2.setLine(l1).show(); l3.show(); l4.setLine(t,q).show();}代码
#include<iostream>using namespace std;class Point{ friend class Line;private: double x,y;public: Point(double a=0,double b=0):x(a),y(b){cout<<"Point : ("<<x<<", "<<y<<") is created."<<endl;} Point(const Point&p){x=p.x;y=p.y;cout<<"Point : ("<<x<<", "<<y<<") is copied."<<endl;} ~Point(){cout<<"Point : ("<<x<<", "<<y<<") is erased."<<endl;} void show(){cout<<"Point : ("<<x<<", "<<y<<")"<<endl;}};class Line{ friend class Point;private: Point p1,p2;public: Line(Point &p,Point &q):p1(p),p2(q){cout<<"Line : ("<<p1.x<<", "<<p1.y<<") to ("<<p2.x<<", "<<p2.y<<") is created."<<endl;} Line(double x1=0,double y1=0,double x2=0,double y2=0):p1(x1,y1),p2(x2,y2){cout<<"Line : ("<<p1.x<<", "<<p1.y<<") to ("<<p2.x<<", "<<p2.y<<") is created."<<endl;} Line(const Line&l):p1(l.p1),p2(l.p2){cout<<"Line : ("<<p1.x<<", "<<p1.y<<") to ("<<p2.x<<", "<<p2.y<<") is copied."<<endl;} ~Line(){cout<<"Line : ("<<p1.x<<", "<<p1.y<<") to ("<<p2.x<<", "<<p2.y<<") is erased."<<endl;} Line& setLine(double a,double b,double c,double d){p1.x=a;p1.y=b;p2.x=c;p2.y=d;return *this;} Line& setLine(const Point &p, const Point &q){p1=p;p2=q;return *this;} Line& setLine(const Line& l){*this=l;return *this;} void show(){cout<<"Line : ("<<p1.x<<", "<<p1.y<<") to ("<<p2.x<<", "<<p2.y<<")"<<endl;} void readLine(){char c;cin>>p1.x>>c>>p1.y>>p2.x>>c>>p2.y;}};int main(){ int num, i; Point p(1, -2), q(2, -1), t; t.show(); std::cin>>num; Line line[num]; for(i = 0; i < num; i++) { line[i].readLine(); line[i].show(); } Line l1(p, q), l2(p,t), l3(q,t), l4(l1); l1.show(); l2.setLine(l1).show(); l3.show(); l4.setLine(t,q).show();}
