Need HELP with objects and classes problem (program compiles)

Question

Alright guys, it is a homework problem but I have definitely put in the work. I believe I have everything right except for the toString method in my Line class. The program compiles and runs but I am not getting the right outcome and I am missing parts. I will post my problems after the code. I will post the assignment (sorry, its long) also. If anyone could help I would appreciate it. It is due on Monday so I am strapped for time.
Assignment:
-There are two ways to uniquely determine a line represented by the equation y=ax+b, where a is the slope and b is the yIntercept.
a)two diffrent points
b)a point and a slope
!!!write a program that consists of three classes:
1)Point class: all data MUST be private
a)MUST contain the following methods:
a1)public Point(double x, double y)
a2)public double x ()
a3public double y ()
a4)public String toString () : that returns the point in the format "(x,y)"
2)Line class: all data MUST be private
b)MUST contain the following methods:
b1)public Line (Point point1, Point point2)
b2)public Line (Point point1, double slope)
b3)public String toString() : that returns the a text description for the line is y=ax+b format
3)Point2Line class
c1)reads the coordinates of a point and a slope and displays the line equation
c2)reads the coordinates of another point (if the same points, prompt the user to change points) and displays the line equation
***I will worry about the user input later, right now I am using set coordinates
What is expected when the program is ran: example
please input x coordinate of the 1st point: 5
please input y coordinate of the 1st point: -4
please input slope: -2
the equation of the 1st line is: y = -2.0x+6.0
please input x coordinate of the 2nd point: 5
please input y coordinate of the 2nd point: -4
it needs to be a diffrent point from (5.0,-4.0)
please input x coordinate of the 2nd point: -1
please input y coordinate of the 2nd point: 2
the equation of the 2nd line is: y = -1.0x +1.0
CODE::
public class Point{
     private double x = 0;
     private double y = 0;
     public Point(){
     public Point(double x, double y){
          this.x = x;
          this.y = y;
     public double getX(){
          return x;
     public double setX(){
          return this.x;
     public double getY(){
          return y;
     public double setY(){
          return this.y;
     public String toString(){
          return "The point is " + this.x + ", " + this.y;
public class Line
     private double x = 0;
     private double y = 0;
     private double m = 0;
     private double x2 = 0;
     private double y2 = 0;
     public Line()
     public Line (Point point1, Point point2)
          this.x = point1.getX();
          this.y = point1.getY();
          this.x2 = point2.getX();
          this.y2 = point2.getY();
          this.m = slope(point1, point2);
     public Line (Point point1, double slope)
          this.x = point1.getX();
          this.y = point1.getY();
     public double slope(Point point1, Point point2)//finds slope
          double m1 = (point1.getY() - point2.getY())/(point1.getX() - point2.getX());
          return m1;
     public String toString()
          double temp = this.x- this.x2;
          return this.y + " = " +temp + "" + "(" + this.m + ")" + " " + "+ " + this.y2;
          //y-y1=m(x-x1)
public class Point2Line
     public static void main(String[]args)
          Point p = new Point(3, -3);
          Point x = new Point(10, 7);
          Line l = new Line(p, x);
          System.out.println(l.toString());
}My problems:
I dont have the right outcome due to I don't know how to set up the toString in the Line class.
I don't know where to put if statements for if the points are the same and you need to prompt the user to put in a different 2nd point
I don't know where to put in if statements for the special cases such as if the line the user puts in is a horizontal or vertical line (such as x=4.7 or y=3.4)
Edited by: ta.barber on Apr 20, 2008 9:44 AM
Edited by: ta.barber on Apr 20, 2008 9:46 AM
Edited by: ta.barber on Apr 20, 2008 10:04 AM

Answer 1

Sorry guys, I was just trying to be thorough with the assignment. Its not that if the number is valid, its that you cannot put in the same coordinated twice.
public class Line
     private double x = 0;
     private double y = 0;
     private double m = 0;
     private double x2 = 0;
     private double y2 = 0;
     public Line()
     public Line (Point point1, Point point2)
          this.x = point1.getX();
          this.y = point1.getY();
          this.x2 = point2.getX();
          this.y2 = point2.getY();
          this.m = slope(point1, point2);
     public Line (Point point1, double slope)
          this.x = point1.getX();
          this.y = point1.getY();
     public double slope(Point point1, Point point2)//finds slope
          double m1 = (point1.getY() - point2.getY())/(point1.getX() - point2.getX());
          return m1;
     public String toString()
          double temp = this.x- this.x2;
          return this.y + " = " +temp + "" + "(" + this.m + ")" + " " + "+ " + this.y2;
          //y-y1=m(x-x1)
public class Point2Line
     public static void main(String[]args)
          Point p = new Point(3, -3);
          Point x = new Point(10, 7);
          Line l = new Line(p, x);
          System.out.println(l.toString());
}The problem is in these lines of code.
public double slope(Point point1, Point point2) //if this method finds the slope than how would i use the the two coordinates plus "m1" to
          double m1 = (point1.getY() - point2.getY())/(point1.getX() - point2.getX());
          return m1;
     public String toString()
          double temp = this.x- this.x2;
          return this.y + " = " +temp + "" + "(" + this.m + ")" + " " + "+ " + this.y2;
          //y-y1=m(x-x1)
     }if slope method finds the slope than how would i use the the two coordinates + "m1" to create a the line in toString?