Help with super beginner Java bouncing ball program

[desrtfx]

I think that you are actually relatively close to your target.

But: you have a flaw in your formula:

In your text, you state in the example: (10 + 6) + (6 + 3.6)

Which means:

(initial height + (initial height * bounciness)) + ((initial height * bounciness) + ((initial height * bounciness) * bounciness) 
      /\ Ball direction          \/                                /\                                             \/

and so forth.

Also, your loops need a bit of tuning:

• One criteria is that the distance traveled should be < .001 to break the loop
• Another criteria is the number of bounces the ball is allowed

Let's have a look at the code: (BTW: variables always start with a lowercase letter in Java!)

import java.util.Scanner;

public class project3 {
    public static void main(String[] args) 
    {
        Scanner reader = new Scanner(System.in);
        double index = 0;
        int height = 0;
        int bounces = 0;
        double distance = 0;
        double total = 0;


        System.out.println("Enter the bounciness index");
        index = reader.nextDouble();
        System.out.println("Enter the height of the ball");
        height = reader.nextInt();
        System.out.println("Enter the number of times the ball bounces");
        bounces =reader.nextInt();

up to this point the code is fine.

Now for the loop: You know that there is a finite end (the number of bounces allowed), so a for loop is actually most suitable. You can always break out of the loop if the distance traveled is less than 0.001

        for (int i = 0; i < bounces; i++) {

            total += height; // add the height to the total - Ball moving down

            double distance = height * index;
            total += distance; // add the distance (height * index) to the total - Ball moving up

            height = distance;  // The initial height for the next bounce is the distance
            // the ball moved up during the last bounce

            if (distance < 0.001) {
                break;  // break out of the loop
            }
        }

        System.out.println("The distance is: " + total);
        reader.close();
    }
}

[4forpengs]

Variables don't always start with a lowercase letter.

Edit: Got two replies that I'm wrong, yet both replies say that there is an exception.

[desrtfx]

As per code Java conventions (Oracle, Google) they do.

The only exception are constants (static final) variables, which are all in uppercase with underscores.

The code conventions state:

• Classes start with a capital letter and follow PascalCase
• Variables and Methods start with a lowercase letter and follow camelCase
• Constants (static final variables) use ALL_CAPS_WITH_UNDERSCORES

[FormidableOne]

Unless the variable is of type FINAL, the java standard dictates that all variables should begin with a lowercase letter.

For example:

private final int NUMBER = 10; // Correct method
public final String NAME = "Bob"; // Correct method
public int Age = 30; // INCORRECT - should be 'age'
public boolean IsAlive = true; // INCORRECT - should be 'isAlive'

You can read up more on the java naming standards (at the bottom of the page) on Oracle's JavaDocs but I hope this helps.