How do I define a java method in a class?

Question

I really hope someone can help me, as I've been sitting and looking at this problem for hours and I think it's just a detail that is missing...but not sure.

I have defined a class Triangle which is supposed to take 3 (x,y) coordinates and from it, calculate sidelengths, corners and area. The class looks like this:

   public class Triangle {
        private double x1, x2, x3, y1, y2, y3;
        double sideA, sideB, sideC;
        private double angleA, angleB, angleC;

        public Triangle(double x1, double y1, double x2, 
            double y2, double x3, double y3) {
        }

        public double getSideA() {
            return (Math.sqrt(Math.pow((x3-x2),2)+Math.pow((y3-y2),2)));
        }
    }

Now I want to call my getSideA method in my Interaction class and. I have defined my coordinate variables and they get their values from scan method. I have also defined a variable sideA, that I want to get the value from my getSideA method. This is how I have done it:

Triangle userTriangle = new Triangle(x1, x2, x3, y1, y2, y3);   

 userTriangle.getSideA = sideA;

When I try to compile the Interaction class I get the following error code:

Interaction.java:79: cannot find symbol
symbol  : variable getSideA
location: class Triangle
     userTriangle.getSideA = sideA;
                 ^

Any ideas what I am doing wrong??

Answer 1

Assignment & function invocation are being performed incorrectly.

sideA =  userTriangle.getSideA();
                               ^parens necessary when calling function

    <---------- (value assigned from right to left)

Assignment occurs from right to left.

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Also, private variables in your class are not being set. You won't end up with the expected result. Set the instance variables within the constructor, using

this.<pvt_var> = value_passed_to_constructor;