point.java

JAVA 2入门经典 练习答案

// Chapter 6 Exercise 6

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

// Constructors:

  public Point() {
    x = 0.0;
    y = 0.0;
  }

  // Construct a Point from its coordinates:
  public Point(double x, double y) {
    this.x = x;
    this.y = y;
  }

  // Construct a Point from another Point:
  public Point(Point point) {
    x = point.x;
    y = point.y;
  }

  // Method to return a point defined relative to this point in coordinates:
  public Point add(Point z) {
    return new Point(x+z.x,y+z.y);
  }

  // Overrides the method inherited from Object:
  public String toString() {
    return "Point: " + x + "," + y;
  }
  
  // Method to test the current object against the argument:
  // returns true if they are equal and false otherwise.
  // This method overrides the method inherited from object.
  public boolean equals(Object point) {
    return x==((Point)point).x && y==((Point)point).y;
  }
}