C++

// 设计一个圆形类（Circle），和一个点类（Point），计算点和圆的关系。
class Circle
{
public:
	int x;
	int y;
	int radius;

};

class Point
{
public:
	int x;
	int y;

	void judge_relation(Circle& c)
	{
		int distance = (x - c.x) * (x - c.x) + (y - c.y) * (y - c.y);
		if (distance == c.radius * c.radius)
			cout << "点在圆上" << endl;
		else if (distance > c.radius * c.radius)
			cout << "点在圆外" << endl;
		else
			cout << "点在圆内" << endl;
	}
};

int main()
{
	Circle c1;
	c1.x = 0;
	c1.y = 1;
	c1.radius = 1;

	Point p1;
	p1.x = 0;
	p1.y = 7;
	p1.judge_relation(c1);

	return 0;
}