#include <iostream>
double Area_circle(double R)
{
static double PI = std::atan(1) * 4;
return PI * (R*R);
}
int main()
{
double r_out, r_in_1, r_in_2, r_in_3;
std::cout << "Enter the radius of the outgoing circles" << std::endl;
std::cin >> r_out;
std::cout << "Enter a radius of 1 inner circle" << std::endl;
std::cin >> r_in_1;
std::cout << "Enter a radius of 2 inner circle" << std::endl;
std::cin >> r_in_2;
std::cout << "Enter a radius of 3 inner circle" << std::endl;
std::cin >> r_in_3;
double S = Area_circle(r_out) - Area_circle(r_in_1) - Area_circle(r_in_2) - Area_circle(r_in_3);
if (S > 0)
{
std::cout << "S == " << S << std::endl;
}
else
{
std::cout << "The inner area of the circles should not be greater than the outer!" << std::endl;
}
system("pause");
return 0;
}