Calculate Distance Traveled (using Methods)

[6r3nt0n]

Hey guys - I need some help...

I'm trying to create a program that calculates Distance Traveled using user-input for their Speed and Time. However, the assignment requires that I write a separate method for the computation of the Distance and another to DisplayData, so I can recall it back in the Main method, then display the results in another method. But - I keep getting some errors. Any help will surely be appreciated. Thanks in advance.

Here's the Errors I'm getting from the compiler:

DistTravel.java:25: error: variable speed might not have been initialized
displayData(speed, time);
^
DistTravel.java:25: error: variable time might not have been initialized
displayData(speed, time);
^
2 errors


P.S. Bare with me on my coding. I am an amateur at Java Programming. Still learning.

import javax.swing.JOptionPane;
import java.io.*;

public class DistTravel
{
	public static void main(String[] args) throws IOException
	{	
		// Declare the variables.
		String input;
		int speed, time;
			
		// The 'Distance Traveled' equation.
		Distance();
		
		// Display Data
		displayData(speed, time);
		
		System.exit(0);
	}
	
	public static int Distance()
	{	
		// Get the vehicle speed from the user.
		
		// Declare the variables
		int speed;
		int time;
		
		String input;	// To hold user's input.
		
		input = JOptionPane.showInputDialog("What is your vehicle's speed in miles-per-hours? ");
		
		// Convert the input to a double.
		speed = Integer.parseInt(input);
		
	   while (speed <= 0)
			{
				input = JOptionPane.showInputDialog("Your speed must be greater than zero. Please re-enter. ");
				
				speed = Integer.parseInt(input);
			}
		
		// Get the hours traveled from the user.
		input = JOptionPane.showInputDialog("How many hours have you traveled, thus far? ");
		
			time = Integer.parseInt(input);
		
	   while (time <= 1)
		{
				input = JOptionPane.showInputDialog("How many hours have you traveled for? ");
			
				time = Integer.parseInt(input);
		}
				
		return speed * time;
	}
	
	public static void displayData(int speed, int time)
	{		
		for(int i = 1; i <= time; i++)
			{
			JOptionPane.showMessageDialog(null, "Hour(s): Distance Traveled" + 
			"----------------------------" + "Hour" + ": " + i + (speed * i) + " miles traveled");
			}
	}
}

[keang]

The error messages tell you what is wrong ie:

variable speed might not have been initialized: means the variable called 'speed' is being used before you have definitely assigned a value to it - remember class and instance variable are given default values when they are declared but local variables are not.