定义一个 Shape 抽象类，在此基础上派生出 Rectan

[问答题]

定义一个 Shape 抽象类，在此基础上派生出 Rectangle 和 Circle，二者都有 GetArea()函数计算对象的面积，GetPerim()函数计算对象的周长。

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1185925亓乂

解：

源程序：

#include <iostream.h>
class Shape
{
public:
Shape(){}
~Shape(){}
virtual float GetArea() =0 ;
virtual float GetPerim () =0 ;
};
class Circle : public Shape
{
public:
Circle(float radius):itsRadius(radius){}
~Circle(){}
float GetArea() { return 3.14 * itsRadius * itsRadius; }
float GetPerim () { return 6.28 * itsRadius; }
private:
float itsRadius;
};
class Rectangle : public Shape
{
public:
Rectangle(float len， float width): itsLength(len)， itsWidth(width){};
~Rectangle(){};
virtual float GetArea() { return itsLength * itsWidth; }
float GetPerim () { return 2 * itsLength + 2 * itsWidth; }
virtual float GetLength() { return itsLength; }
virtual float GetWidth() { return itsWidth; }
private:
float itsWidth;
float itsLength;
};
void main()
{
Shape * sp;
sp = new Circle(5);
out << "The area of the Circle is " << sp->GetArea () << endl;
cout << "The perimeter of the Circle is " << sp->GetPerim () << endl;
delete sp;
sp = new Rectangle(4，6);
cout << "The area of the Rectangle is " << sp->GetArea() << endl;
cout << "The perimeter of the Rectangle is " << sp->GetPerim () << endl;
delete sp;
}

程序运行输出：

The area of the Circle is 78.5

The perimeter of the Circle is 31.4

The area of the Rectangle is 24

The perimeter of the Rectangle is 20

发表于 2018-04-18 20:37:39 回复(0)

C语言菜鸡

Shape.h:
class Shape{
public:
	Shape(){};
	~Shape(){};
	virtual double GetArea()=0;
	virtual double GetPerim()=0;
};
class Rectangle:public Shape{
private:
	double x,y,z;
public:
	Rectangle(double x1,double y1,double z1):x(x1),y(y1),z(z1){};
	Rectangle(){};
	virtual double GetArea(){
		double q=(x+y+z)/2.0;
		return sqrt(q*(q-x)*(q-y)*(q-z));
	};
	virtual double GetPerim(){return x+y+z;};
};
class Circle:public Shape{
private:
	double r;
public:
	Circle(){};
	Circle(double r1):r(r1){};
	virtual double GetArea(){
		return 3.14*r*r;
	};
	virtual double GetPerim(){ return 2*3.14*r;};
};
Main.cpp:
#include<iostream>
(720)#include<math.h>
#include"Shape.h"
using namespace std;
int main(){
	double x,y,z,r;
	cout<<"input x,y,z:";
	cin>>x>>y>>z;
	Shape *p=new Rectangle(x,y,z);
	cout<<"Area:"<<p->GetArea()<<endl;
	cout<<"Perim:"<<p->GetPerim()<<endl;
	cout<<"input r:";
	cin>>r;
	p=new Circle(r);
	cout<<"Area:"<<p->GetArea()<<endl;
	cout<<"Perim:"<<p->GetPerim()<<endl;
	return 0;
}

输出结果：

input x,y,z:2 2 2
Area:1.73205
Perim:6
input r:1
Area:3.14
Perim:6.28

发表于 2020-03-26 16:53:32 回复(0)

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问题信息

C++

上传者：1185925亓乂

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定义一个 Shape 抽象类，在此基础上派生出 Rectan

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