打卡23

#include <string>
#include<iostream>
using namespace std;
#define PI 3.14159f
class Shape
{public:
	virtual void set() = 0;
	virtual float getarea() = 0;
};
class Circle :public Shape
{
private:
	float r;
public:
	void set()
	{
		cin >> r;
	}
	float getarea()
	{
		return PI * r * r;
	}
};
class Square :public Shape
{
private:
	float d;
public:
	void set()
	{
		cin >> d;
	}
	float getarea()
	{
		return d*d;
	}
};
class Rectangle :public Shape
{
private:
	float l,h;
public:
	void set()
	{
		cin >> l>>h;
	}
	float getarea()
	{
		return l * h;
	}
};
class Trapezoid :public Shape
{
private:
	float a,b,c;
public:
	void set()
	{
		cin >> a>>b>>c;
	}
	float getarea()
	{
		return ((a + b) * c) / 2;
	}
};
class Triangle :public Shape
{
private:
	float a,b;
public:
	void set()
	{
		cin >> a>>b;
	}
	float getarea()
	{
		return a*b/2;
	}
};
void get(Shape& s)
{
	s.set();
}
float getwork(Shape &s)
{
	return s.getarea();
}
int main()
{
	Circle c;
	Square s;
	Rectangle r;
	Trapezoid t;
	Triangle t1;
	get(c);
	get(s);
	get(r);
	get(t);
	get(t1);
	printf("%.3f\n", getwork(c) + getwork(s) + getwork(r) + getwork(t) + getwork(t1));
}