1 #include <iostream>
2
3 using namespace std;
4 const double PI=3.14;
5
6 class Ellipse
7 {
8 private:
9 int x,y;
10 double a,b;
11 double area;
12 public:
13 Ellipse(int,int,double,double);
14 double Area();
15 };
16
17 Ellipse::Ellipse(int x, int y, double a, double b)
18 {
19 this->x=x;
20 this->y=y;
21 this->a=a;
22 this->b=b;
23 }
24
25 double Ellipse::Area()
26 {
27 return PI*a*b;
28 }
29
30 int main()
31 {
32 int x,y;
33 double a,b;
34 cin>>x>>y>>a>>b;
35 Ellipse one(x,y,a,b);
36 cout<<one.Area()<<endl;
37 return 0;
38 }