[C++] 명품 c++ 프로그래밍 실습 5장 1번

#include <iostream>
using namespace std;

class Circle {
	int radius;
public:
	Circle();
	Circle(int r);
	//Circle(int radius) { this->radius = radius; }
	double getArea() { return 3.14*radius*radius; }
};
Circle::Circle() {
	radius = 1;
}
Circle::Circle(int r) {
	radius = r;
}
void swap(int &a, int &b) {
	int tmp;
	tmp = a;
	a = b;
	b = tmp;
}
int main() {
	Circle x;
	Circle y(30);
	cout << x.getArea() << " " << y.getArea() << endl;
	swap(x, y);
	cout << x.getArea() << " " << y.getArea() << endl;
}