Thread: Point constructor

Hi,

I'm a newbie in programming, trying to work on a practice problem in classes and objects. I tried the following to construct Point of type double, but when I print Point C, it prints 0,0; can someone take a look and guide where I'm getting this wrong..

thanks,
upad

-----------------------------------------------------------------------------------

 
public class Point
{
	private int x;
	private int y;
	private double a;
	private double b;
 
	//constructs a new point with (0,0) as coordinates
	public Point()
	{
		x=0;
		y=0;
	}
 
	//constructs a new point with the given (x,y) location
	public Point(int initialX, int initialY)
	{
		x = initialX;
		y = initialY;
	}
 
	//constructs a new point with coordinates of type double
	public Point(double initialX, double initialY)
	{
 
		if((initialX-(int) initialX)>0.5)
			a=(int)initialX + 1;
		//else
		//	initialX=initialX;
 
		if((initialY-(int) initialY)>0.5)
			b=(int)initialY + 1;
		//else
		//	initialY=initialY;	
	}
 
	//returns the x-coordinate of this point
	int getX()
	{
		return x;
	}
 
	//returns the y-coordinate of this point
	public int getY()
	{
		return y;
	}
}
---------------------------------------------
 
public class ReferenceMystery3 {
 
 public static void main(String[] args) {
 
double x = 3.1;
 
double y = 3.9;
 
Point A = new Point();
 
Point B = new Point(3,6);
 
Point C = new Point(x,y);
 
System.out.println(A);
 
System.out.println(B);
 
System.out.println(C);
 
  }
 
}
 
------------------------------------------------
 
Output:
 
(0,0)
 
(3,6)
 
(0,0)

Please fix your post by reading the directions in my signature.

I found your issue. Let me ask you a question: Where do you set the x and y variables in the constructor that takes in two doubles?

Originally Posted by upad

My code does not work as expected which is:
(0,0)
(3,6)
(3.1,4.0)

Actual result:
(0,0)
(3,6)
(0,0)

the reason for 4 class vaiables is to include different data types i.e int and double, but probably this is wrong and I am not sure how to do this

Ok, so you are not wanting to cast your doubles as ints, like you have here:

if((initialX-(int) initialX)>0.5)
            a=(int)initialX + 1;
 
        if((initialY-(int) initialY)>0.5)
            b=(int)initialY + 1;

So, since you want to be able to return double coordinates when you give double coordinates, it is true we want to handle the two cases different. What you need to do though is somehow tell the program if you use the double constructor or not.

I'm sure there is an easier way, but I would modify it to have a boolean. That boolean will be true if the object was constructed with the double constructor, and false if with the other two constructors. I would then make the variables x and y doubles instead of ints. You can then set the x and y variables to ints for the two constructors that do not use doubles and you can still set the double constructor with the same variable. Then you need to make the getX() and getY() methods to return doubles. Lastly, you need to do a check for your boolean in your toString method. Basically, if the boolean is false, cast the x and y variables as ints before printing them out.

I wanted to explain how to do this, instead of coding it for you. Tell me if you understand everything and if you need help I'll provide what I can.