Error accessing class from method

Question

I am trying to write a method that accesses a class called circle where the user inputs the radius of a circle and the program prints the area, radius and circumference.
My class is as follows.
public class Circle
private double Radius;
private double PI = 3.14159;
public void setRadius(double rad)
Radius = rad;
public void setPI(double pi)
PI = pi;
public double getRadius()
return Radius;
public double getPI()
return PI;
public double getArea()
return PI * Radius * Radius;
public double getDiameter()
return Radius * Radius;
public double getCircumferance()
return 2 * PI * Radius;
I am not having any areas when compiling the class.
The method is as follows.
//IS 115
//DED01
//Method for Circle class
//Larry Piatt
public class CircleStats
public static void main(String[] args)
double number;
Scanner keyboard = new Scanner(System.in);
Circle Radius = new Circle();
Circle Area = new Circle();
Circle Diameter = new Circle();
Circle Circumference = new Circle();
System.out.println("What is the radius of the circle? ");
number = keyboard.nextDouble();
number.setRadius(number);
System.out.println("The area of the circle is "
+ Area);
System.out.println("The diamter of the circle is "
+ Diameter);
System.out.println("The circumference of the circle is "
+ Circumference);
The error that I am seeing are as follows
^
CircleStats.java:28: double cannot be dereferenced
number.setRadius(number);
^
1 errors
This is my first attempt at writting a method that calls a class. I am not understanding it very well yet. Any assistance would be greatly appreciated.
Edited by: tooned on Mar 30, 2008 1:10 PM

Answer 1

1) your error: You're trying to call a method, setRadius, on the variable, number, which is nothing more than a lowly double primative variable. Better to call the method on your Circle object which here you call "Radius" (please note the Java naming convention: objects should begin with a lower-case letter).
Also, when posting your code, please use code tags so that your code will retain its formatting and be readable. To do this, either use the "code" button at the top of the forum Message editor or place the tag [code] at the top of your block of code and the tag [/code] at the bottom, like so:
[code]
  // your code block goes here.
  // note the differences between the tag at the top vs the bottom.
[/code]or
{code}
  // your code block goes here.
  // note here that the tags are the same.
{code}Your formatted code would look something like so:
public class Circle
    private double Radius;
    private double PI = 3.14159;
    public void setRadius(double rad)
        Radius = rad;
    public void setPI(double pi)
        PI = pi;
    public double getRadius()
        return Radius;
    public double getPI()
        return PI;
    public double getArea()
        return PI * Radius * Radius;
    public double getDiameter()
        return Radius * Radius;
    public double getCircumferance()
        return 2 * PI * Radius;
import java.util.Scanner;
class CircleStats
    public static void main(String[] args)
        double number;
        Scanner keyboard = new Scanner(System.in);
        Circle Radius = new Circle();
        Circle Area = new Circle();
        Circle Diameter = new Circle();
        Circle Circumference = new Circle();
        System.out.println("What is the radius of the circle? ");
        number = keyboard.nextDouble();
        // number.setRadius(number);
        Radius.setRadius(number);
        System.out.println("The area of the circle is " + Area);
        System.out.println("The diamter of the circle is " + Diameter);
        System.out.println("The circumference of the circle is "
                + Circumference);
}