第六章作业

小灰灰 2022-08-01 11:27 195阅读 0赞

第六章  作业

1. \#include <iostream.h>  
class Point  
\{public:  
Point(float x=0,float y=0);  
void setPoint(float,float);  
float getX() const  
\{return x;\}  
float getY() const  
\{return y;\}  
friend ostream & operator<<(ostream &output,Point &);  
protected:  
float x,y;  
\};  
Point::Point(float a,float b)  
\{  
x=a;y=b;  
\}  
void Point::setPoint(float a,float b)  
\{  
 x=a;y=b;  
\}  
ostream & operator<<(ostream &output,Point &p)  
\{  
 output<<"\["<<p.x<<","<<p.y<<"\]"<<endl;  
 return output;  
\}  
class Circle:public Point  
\{  
public:  
Circle(float x,float y,float r):Point(x,y),radius(r)\{\}  
void setRadius(float r)  
\{radius=r;\}  
float getRadius() const  
\{return radius;\}  
double area() const  
\{  
return 3.1415\*radius\*radius;  
\}  
friend ostream & operator<<(ostream &output,Circle &);  
protected:  
float radius;  
\};  
ostream & operator<<(ostream &output,Circle &c)  
\{  
output<<"Center =\["<<c.x<<","<<c.y<<"\],r= "<<c.radius<<",area="<<c.area()<<endl;  
return output;  
\}  
class Cylinder:public Circle  
\{  
public:  
Cylinder(float x,float y,float r,float h):Circle(x,y,r),height(h)\{\}  
void setHeight(float h)  
\{height=h;\}  
float getHeight() const  
\{return height;\}  
double area() const  
\{  
return 2\*Circle::area()+2\*3.1415\*radius\*height;   
\}  
double volume() const  
\{  
   return 3.1415\*radius\*radius\*height;  
\}  
friend ostream & operator<<(ostream &output,Cylinder &);  
protected:  
float height;  
\};  
ostream & operator<<(ostream &output,Cylinder &cy)  
\{  
 output<<"Center=\["<<cy.x<<cy.y<<"\],r="<<cy.radius<<",h="<<cy.height<<"\\narea="<<cy.area()<<",volume="<<cy.volume()<<endl;  
 return output;  
\}  
int main()  
\{  
 Cylinder cy1(3.5,6.4,5.2,10);  
 cout<<"original cylinder:\\nx="<<cy1.getX()<<",y="<<cy1.getY()<<",r="<<cy1.getRadius()<<",h="<<cy1.getHeight()<<"\\narea="<<cy1.area()<<",volume="<<cy1.volume()<<endl;  
 cy1.setHeight(15);  
 cy1.setRadius(7.5);  
 cy1.setPoint(5,5);  
 cout<<"\\nnew cylinder:\\n"<<cy1;  
 Point &pRef=cy1;  
 cout<<"\\npRef as a point:"<<pRef;  
 Circle &cRef=cy1;  
 cout<<"\\ncRef as a circle:"<<cRef;  
 return 0;  
\}

3.（2） \#include <iostream>  
using namespace std;  
class Point  
\{  
 public:  
Point(float a,float b):x(a),y(b)\{\}  
~Point()\{cout<<"executing Point destructor"<<endl;\}  
 private:  
float x;  
float y;  
\};  
class Circle:public Point  
\{  
public:  
Circle(float a,float b,float r):Point(a,b),radius(r)\{\}  
~Circle()\{cout<<"executing Circle destructor"<<endl;\}  
private:  
float radius;  
\};  
int main()  
\{  
 Point \*p=new Circle(1,2,3);  
 Circle \*r=new Circle(1,2,3);  
 delete r;  
 return 0;  
\}

![Center][]

[Center]: /images/20220731/9bdc713527044ee0aab4557f9aed8450.png