Thread: Little help with "extends" please

I have to extend a class from squareDemo in this assignment. All i need to do is add depth to the compute surface area arithmetic. It wont allow me to print in the extended class. I also cant grab height, width from the parent class which I "thought" was the purpose of inheritance. Please help with code and explain how my logic is flawed. I'm a new programmer so please go easy on me heh...

package square;
 
/**
 *
 * @author Michael
 * Chapter 9 exercise 2
 */
public class SquareDemo
{
    public static void main(String[] args)
    {
        int height = 6;
        int width = 6;
        int surfaceAreaSQ = height * width;
 
        System.out.println("The surface area of the square is: " + surfaceAreaSQ);
    }
 
    public class CubeDemo extends SquareDemo
    {
        int height = 6;
        int width = 6;
        int depth = 6;
        int surfaceAreaCU = height * width * depth;
 
        System.out.println("The surface area of the cube is: " + surfaceAreaCU);
 
 
    }
 
}

Okay scratch the last code. This code actually looks like it's going to work. I'm getting one error in the main. non-static variable cannot be used in static context. It's odd because the few lines above the error is basically doing the same thing without error. Check this out please.

/**
 *
 * @author Michael Bowers
 * Chapter 9 - Assignment 2
 */
public class Square
{
    int height;
    int width;
    int surfaceArea;
 
//********** CONSTRUCTOR Square **********
    public Square(int h, int w)
    {
        height = h;
        width = w;
    }//___________ END Constructor ________
 
    public void DisplaySquare()
    {
        System.out.println("The surface area of the square is: " + surfaceArea);
    }
 
    public void computeSurfaceArea()
    {
       surfaceArea = height*width;
    }
 
//********** Extends Square **********
    public class Cube extends Square
    {
        int depth;
 
 //********** CONSTRUCTOR Cube **********       
        public Cube( int h, int w, int d)
        {
          super(h, w);
          depth = d;
        }//_______ END Constructor _______
 
        public void computeSurfaceArea()
        {
            super.computeSurfaceArea();
            surfaceArea = surfaceArea * depth;
        }
 
    }//_____ END Class Cube ______
 
    public void DisplayCube()
    {
        System.out.println("The surface area of the cube is: " + surfaceArea);
    }
 
 
    public static void main(String[] args)
    {
        Square square1 = new Square(6, 6);
        square1.computeSurfaceArea();
        square1.DisplaySquare();
 
        Cube cube1 = new Cube(6, 6, 6);
        cube1.computeSurfaceArea();
        cube1.DisplayCube();
    }
 
}

please surround your code with [code] tags please

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// I don't know where the solved button resides.

Originally Posted by uzisuicide

if (problem == solved)
     select Solved;
else
     don't;
 
// I don't know where the solved button resides.

The 'Mark Thread As Solved' button is in Thread Tools at the top of the forums.

I have done it for you this time