Thread: Conversion Program

So for my CIS class, I need to write a program that converts inputed meters into either kilometers, inches, or feet based off of a menu provided to the user and their input. the meters entered cannot be negative, and if the menu option is outside of the 1-4 option range, it should be invalid. I am getting errors for :

java: method showKilometers in class challenge8 cannot be applied to given types;
required: double
found: no arguments
reason: actual and formal argument lists differ in length

java: method showInches in class challenge8 cannot be applied to given types;
required: double
found: no arguments
reason: actual and formal argument lists differ in length

java: method showFeet in class challenge8 cannot be applied to given types;
required: double
found: no arguments
reason: actual and formal argument lists differ in length

Thank you in advanced for any help.

here is my code:

import javax.swing.JOptionPane;
 
public class challenge8
{
    public static void main(String[] args)
    {
    double meters;
    double kilometers;
    double inches;
    double feet;
    int menuItem;
 
    meters = getMeters();
    menuItem = menu();
    kilometers = showKilometers();
    inches = showInches();
    feet = showFeet();
 
        while (menuItem < 0 || menuItem > 4)
        {
            JOptionPane.showMessageDialog(null,"That is an invalid menu option.");
            menu();
        }
 
        if (menuItem == 1)
        {
            JOptionPane.showMessageDialog(null, meters + " meters is " + kilometers + " kilometers.");
        }
        else if (menuItem == 2)
        {
            JOptionPane.showMessageDialog(null, meters + " meters is " + inches + " inches.");
        }
        else if (menuItem == 3)
        {
            JOptionPane.showMessageDialog(null, meters + " meters is " +  feet + " feet.");
        }
        else if (menuItem == 4)
        {
                System.exit(0);
 
        }
      System.exit(0);
    }
 
    public static double getMeters()
    {
       String input;
       double numMeters;
 
       input = JOptionPane.showInputDialog("Please enter a distance in meters.");
       numMeters = Double.parseDouble(input);
 
        if (numMeters < 0){
            JOptionPane.showMessageDialog(null, "Meter can not be negative.");
        }
 
        return numMeters;
 
    }
 
    public static double showKilometers(double numMeters)
    {
     return numMeters * 0.001;
    }
 
    public static double showInches(double numMeters)
    {
     return numMeters * 39.37;
    }
 
    public static double showFeet(double numMeters)
    {
      return numMeters * 3.281;
    }
 
    public static int menu()
    {
 
        String input;
        int choice;
 
        input = JOptionPane.showInputDialog("Please choose one of the following:\n 1. Convert to kilometers\n" +
                                             " 2. Convert to inches\n 3. Convert to feet\n 4. Quit the program");
        choice = Integer.parseInt(input);
 
        return choice;
 
 
    }
}

--- Update ---

I fixed the method error, I just had to pass meters into the methods.

howver now my loop is messed up. It will work if on the first try, the option entered is 1-4, but if it is outside that range, the second time, no matter what the number is, it still says it is invalid.

After a bit of toying with it and referring back to my Java textbook. I was able to make it work. Thank you for help though.