Question

在线急求一个c++习题

要求使用指向类成员函数的指针实现多态性 来计算来计算，正方行，矩形，直角三角形和圆的面积 O(∩_∩)O谢谢 没有积分了帮帮我把

Answer 1

#include <iostream>
using namespace std;

const double PI=3.14;

class Sharp
{
public:
virtual void Area()=0;
float area;
};

class Rect:public Sharp
{
public:
Rect(float x,float y):length(x),heigth(y){};
void Area()
{
area=length*heigth;
printf("Rect area:%.2f\n",area);
}
private:
float length,heigth;
};

class Square:public Sharp
{
public:
Square(float x):length(x){};
void Area()
{
area=length*length;
printf("Square area:%.2f\n",area);
}
private:
float length;
};

class Circle:public Sharp
{
public:
Circle(float r):radius(r){};
void Area()
{
area=PI*radius*radius;
printf("Circle area:%.2f\n",area);
}
private:
float radius;
};

class Triangle:public Sharp
{
public:
Triangle(float x,float y):length(x),heigth(y){};
void Area()
{
area=0.5*length*heigth;
printf("Triangle area:%.2f\n",area);
}
private:
float length,heigth;
};

int main(void)
{
Sharp *p1;
Rect a(1,2);
p1=&a;
p1->Area();

Square b(4);
p1=&b;
p1->Area();

Circle c(9);
p1=&c;
p1->Area();

Triangle d(2,3);
p1=&d;
p1->Area();

return 0;
}