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......
    string ret;
    void isPointerInCircle(Pointer p) {
        int x1 = center.getX();
        int y1 = center.getY();
        int x2 = p.getX();
        int y2 = p.getY();
        int dist = pow((x2 - x1), 2) + pow((y2 - y1), 2);
        if  (dist > pow(radius, 2)) {
            ret = "out";
        } else if (dist == pow(radius, 2)) {
            ret = "on";
        } else {
            ret = "in";
        }

        cout << ret << 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;
}