public class Point {
  // This class defines the idea of a Point on an x-y graph.  It can be used
  // in problems like Lab 3, where points represent locations of different
  // cities on the map.

  // Declarations -- these define the features of any object (variable)
  // in the class.  For class Point, we need two integers to keep
  // track of the x-y coordinates of each point on the graph. 
  private int xcoord, ycoord;

  // Constructor -- defines how any object declared for this class
  // will have its variables initialized.  For class Point, the
  // two integer parameters identify the initial x-y coordinates
  // of a Point object
  public Point (int x, int y) { xcoord = x; ycoord = y; }
   
  // Methods -- define how any object in the class can be manipulated
  // (changed), combined with another object to compute a result, 
  // pr displayed.  The methods for class Point are:
  //      dostamceTo(Point p)  -- computes the distance from the
  //                     given point to another point p.  The result
  //                     returned is a float.
  //      movePoint(Point p) -- moves a Point from its
  //                     current x-y coordinates to those of Point p.
  //      readPoint() -- reads two integers and assigns them to
  //                     the x and y coordinates of the given point.
  //                     Returns false if Keyboard.eof() occurs.
  //      displayPoint() -- displays the x-y coordinates of the given
  //                     given point.

  public float distanceTo (Point p) {
    float d = (float)Math.sqrt(Math.pow(p.xcoord - xcoord, 2) +
                               Math.pow(p.ycoord - ycoord, 2));
    return d;
  }
  
  public void movePoint(Point p) {
    xcoord = p.xcoord; ycoord = p.ycoord;
  }
  
  public boolean readPoint() {
    System.out.print("x coordinate: "); xcoord = Keyboard.readInt();
    if (!Keyboard.eof()) {
      System.out.print("y coordinate: "); ycoord = Keyboard.readInt(); 
      return true;
    }
    else return false;
  }

  public void displayPoint() {
      System.out.print(" (" + xcoord + ", " + ycoord + ") ");
  }
}

public class CityTour {
// This program computes the total distance of a city tour by Paulo, beginning
// and ending at city A.  He travels through an arbitrary number of cities 
// during his tour.

  public static void main (String[] args) {
  
    Point cityA = new Point(0, 0);     // city A, where Paulo starts and ends
    Point cityLast = new Point(0, 0);  // last city read
    Point cityNext = new Point(0, 0);  // next city read
    float totalDistance = 0;           // and total distance traveled so far.
    
    System.out.println("Enter the coordinates of city A: ");
    cityA.readPoint();
    cityLast.movePoint(cityA);         // start out with last city as city A
    
    System.out.println("Enter coordinates of next city, or ctrl-c: ");
    while (cityNext.readPoint()) {
      totalDistance = totalDistance + cityLast.distanceTo(cityNext);
      cityLast.movePoint(cityNext); 
      System.out.println("Enter coordinates of next city, or ctrl-c: ");      
    } 
    totalDistance = totalDistance + cityLast.distanceTo(cityA);
    System.out.println("Total distance of Paulo's tour = " + totalDistance);
    System.out.print("starting and ending at ");
    cityA.displayPoint();
  }

}