Related to Point

I need to make a method like so

Code:

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public String TriangleType(Point a, Point b, Point c)

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which will return the values either Equilateral, Isosceles, or Scalar.

so far this is what I have:

Code:

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    length1 = Math.sqrt(Math.pow((y2 - y1),2) + Math.pow((x2 - x1),2));
        length2 = Math.sqrt(Math.pow((y3 - y2),2) + Math.pow((x3 - x2),2));
        length3 = Math.sqrt(Math.pow((y1 - y3),2) + Math.pow((x1 - x3),2));
        System.out.printf("(" + x1 + ", " + y1 + ")" + "(" + x2 + ", " + y2
                          + ")" + "(" + x3 + ", " + y3 + ")");
        System.out.printf("|(%.3f, %.3f, %.3f)",length1, length2, length3);
        System.out.println();
        if ((length1 != length2) && (length2 != length3))
          { System.out.println("SC"); return "SC"; }
        else if ((length1 == length2) && (length1 == length3))
          { System.out.println("EQ"); return "EQ"; }
        else { System.out.println("IS"); return "IS"; }

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One thing I don't understand is where to use point a, b, and c.

I also have a subclass of Point which I don't quite understand either. If someone could help me out with this please let me know. I can add information as needed.

Well, your code isn't in a method, so how is it even runnable?

Your code block is looking at the x,y coordinates of the points. You need three points to make a triangle right? So what don't you understand?

Quote:

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Originally Posted by quad64bit

Well, your code isn't in a method, so how is it even runnable?

Your code block is looking at the x,y coordinates of the points. You need three points to make a triangle right? So what don't you understand?

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The code is actually in the TriangleType () {} method. My problem is that I have another method that generates three points x1, y1, x2, y2, x3, y3 and also puts it in a file.

Code:

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public void GenerateRandomTriangles(int numTriangles) {
        int max = 150, x1, y1, x2, y2, x3, y3;
        String str = "(%3d, %3d) (%3d, %3d) (%3d, %3d)";
        Random rand = new Random(0);
        try {
            PrintWriter outFile = new PrintWriter("Triangle.txt");
            Scanner scan = new Scanner(new File("Triangle.txt"));
            //try {
            //numTriangles = scan.nextInt(); scan.nextLine();
            //} catch (NoSuchElementException nse) {
            //    System.out.print(" ");
            //}
            outFile.println("5 //numTriangles; each line below gives integer"
                  + "coordinates (x, y) of verticies of a triangle ");
            for (int i = 0; i < numTriangles; i++) {
                x1 = rand.nextInt(max); y1 = rand.nextInt(max);
                x2 = rand.nextInt(max);
                do { y2 = rand.nextInt(max);
                } while ((y1 == y2));
                do {x3 = rand.nextInt(max);
                } while ((x3 == x1));
                do {y3 = rand.nextInt(max);
                } while (y3 == y2 || (y2 - y1)*(x3 - x1) ==
                        (y3 - y1)*(x2 - x1));   
                outFile.printf(str, x1, y1, x2, y2, x3, y3);
                outFile.println();
            }
        outFile.close();           
        } catch (FileNotFoundException e) {
            System.out.println("cannot create Triangle.txt");
            System.exit(0);}
}

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As you can see the generation of the points occurs in a for loop which I have numTriangles set to five. What I need it to do is communicate with the method TriangleType() { } as each iteration of the loop occurs to calculate the kind of triangle that is generated 5 times. A big thing is I need to create a subclass called Point which I believe is where I should do this. I may have jumped the gun with defining the variables in GenerateRandomTriangles() {} method but I need each definition of each x and y variable to transfer from one method to another and eventually come together in a TestTriangle() {} mehtod that with print the points and the kind of triangles for five different set of points(for five different triangles) with a couple of other prompts. Any kind of directional help will do. I have a couple a read file things there too but I really need to focus on distributing the points around effectively and more important; efficiently.

So if the method needs to return a special type of point (a subclass of point), thats easy enough to do. If it needs to return a collection of points, you can do that too with lists or arrays, or even a custom data type.

Are you unsure how to subclass a class?

Are you unsure how to subclass a class?[/QUOTE]

That seems to be my main problem. I do not have a lot of experience with subclasses. if someone can help me understand how to implement it maybe with an example of some sort closely related to what I described in the above post it would help me out a great deal.

Why do you need a subclass called Point? The Java API already has a class called Point which holds the x and y co-ords. If you really do need a subclass, what is it a subclass of?

BTW, back to basics. To write a subclass it needs to extend the superclass.

Junky is correct on both counts. If you must subclass Point (instead of just using an instance of it) then you need to make a new class. This might help: Inheritance (The Java™ Tutorials > Learning the Java Language > Interfaces and Inheritance)