Need help in creating a java program

Question

Hi everyone.
I'd like to say before i start about my problem, that i've only begun learning java and my teacher hasn't explained anything at all. He only showed us by doing it himself and then showing us the final version. I've searched a little on how to program but i get little success in finding a good tutorial.
I need help creating a program which has been assigned to me due in a few days in which i can't contact my teacher for help.
I need to write a java program which inputs 3 items. The number of kilometres you drove, the number of litres of gas you used and the price you paid for the gas. Then, the program must calculate the number of litres used per 100km driven, which is litres divided by kilometres times 100, how much it costs to drive 100km, which is the result (a) times the price per litre and the number of miles per American gallon of gas ( one American gallon = 3.785 litres, and one mile = 1.609 km.
The program has to output my name, the inputs given, the results computed and a message saying "Program Complete".
To give you what i've done to begin with, from what i understood, is:
import javax.swing.JOptionPane;
public class prog1
     public static void main(String args[])
          final double americanGallon = 3.785;
          final double mile = 1.609;
          kilometresDriven,
          gasUsed;
          priceOfLiterGas;
          System.out.println("My Name");
          System.out.println("Number of kilometres driven:");
          kilometresDriven = JOptionPane.showInputDialog ("Kilometres Driven");
          System.out.println("Number of Litres of gas used:");
          gasUsed = JOptionPane.showInputDialog ("Litres of gas used");
          System.out.println("Price of a liter of gas:");
          priceOfLiterGas = JoptionPane.showInputDialog("Price per liter");
Up to now, that's all i've got. i know i'm wrong, but i'm not sure how to do this. Could someone give me an outline of what this program is suppose to look like?
Thanks in advance.

Answer 1

Here's an update on my program. I've worked on certain details and would need your comments whether it contains errors. I'd also want to know if it would work or not because i don't know how to check it on my computer.
Here's the update:
import javax.swing.JOptionPane;
public class Prog1
public static void main(String args[])
String name;
double kmDriven;
double litresUsed;
double pricePaidForGas;
double priceOfALiter;
name = JOptionPane.showInputDialog("Name");
input = JOptionPane.showInputDialog("Number of km driven");
kmDriven = Double.parseDouble (input);
input = JOptionPane.showInputDialog("Number of litres of gas used");
litresUsed = Double.parseDouble (input);
input = JOptionPane.showInputDialog("Price paid for gas");
pricePaidForGas = Double.parseDouble (input);
input = JOptionPane.showInputDialog("Price of a litre of gas");
priceOfALiter = Double.parseDouble (input);
a = (litresUsed/kmDriven)*100;
b = ((litresUsed/kmDriven)*100)*priceOfALiter);
c = (kmDriven/1.609)
System.out.println("Name:" + name);
System.out.println("Number of litres used per 100km:" + a);
System.out.println("Cost of driving 100km" + b);
System.out.println("Number of miles per American Gallon of Gas:" + c);
System.out.println("Program Complete");
System.exit(0);
Comments please.
Thanks in advance