题解 | #点和圆的关系#

#include <iostream>
#include <cmath>
using namespace std;

// 点类
class Pointer {

    private:
        int x;  // x 坐标
        int y;  // y 坐标

    public:
        void setX(int x) {
            this->x = x;
        }

        int getX() {
            return x;
        }

        void setY(int y) {
            this->y = y;
        }

        int getY() {
            return y;
        }

};

// 圆类
class Circle {

    private:
        Pointer center; // 圆心
        int radius; // 半径

    public:
        void setCenter(int x, int y) {
            center.setX(x);
            center.setY(y);
        }

        void setRadius(int radius) {
            this->radius = radius;
        }
    
        // write your code here......
        void isPointerInCircle(Pointer p) {
            double direction = sqrt(pow(p.getX() - this -> center.getX(), 2) + pow(p.getY() - this -> center.getY(), 2));
            if (direction == radius) {
                cout << "on" << endl;
            } else if (direction < radius) {
                cout << "in" << endl;
            } else {
                cout << "out" << endl;
            }
        }



};

int main() {

    // 键盘输入点的坐标
    int x, y;
    cin >> x;
    cin >> y;

    // 创建一个点
    Pointer p;
    p.setX(x);
    p.setY(y);

    // 创建一个圆
    Circle c;
    c.setCenter(5, 0);
    c.setRadius(5);

    // 判断点和圆的关系
    c.isPointerInCircle(p);

    return 0;
}