Java_学习_静态变量的方法 和 对象的构造函数

计算两点之间的距离

public class Point {
  private double x;
  private double y;

  public Point(double x, double y) {
    this.x = x;
    this.y = y;
  }

  public static double distance(Point p1, Point p2) {//静态的方法
    double dx = p1.x - p2.x;
    double dy = p1.y - p2.y;
    return Math.sqrt(dx * dx + dy * dy);
  }

  public double distance(Point p) {
    double dx = this.x - p.x;
    double dy = this.y - p.y;
    return Math.sqrt(dx * dx + dy * dy);
  }

  public static void main(String[] args) {
    Point p1 = new Point(1.0, 1.0);
    Point p2 = new Point(5.0, 6.0);
    System.out.println(p1.distance(p2));///对象引用
    System.out.println(distance(p1, p2));///静态变量直接引用
  }
}