面向对象——坐标点

/**
 * 封装:坐标点相关的属性、方法代码
 * 封装成Point类
 */
public class Point {
    int x;
    int y;
    public double distance(){
        return Math.sqrt(x*x+y*y);
    }
    public String toString() {
        return "("+x+","+y+")";
    }
}