예제 3-1

#include <iostream>
using namespace std;
class Circle {
public:
    int radius;
    double getArea();
};

double Circle::getArea() {
    return 3.14 * radius * radius;
}
int main()
{
    Circle donut;
    donut.radius = 1;
    double area = donut.getArea();//donut 멤버 함수 호출 //getArea함수에 들어가 리턴값 돌아옴
    cout << "donut 면적은 " << area << endl;

    Circle pizza;
    pizza.radius = 30;
    area = pizza.getArea();
    cout << "pizza 면적은 " << area << endl;











}