Thread: Converting double values (0.0-110.0) to a 4.0 Scale (as used in GPA calculation)

Hello,

I am new to programming, but am working on a program that takes 6 inputted grade averages on a scale of 0.0 - 100.0 (exceptions in the case someone has exceeded the traditional 100.0 limit) and then divides it by 6 and returns the value in a dialog box. However, I want to take the values inputted and convert them to a 4.0 scale (90.0-100.0 = 4.0, 80.0-89.99 = 3.0, etc.) and then get the average of that so that I can return an average on a 4.0 scale. I have been trying to accomplish this but haven't been able to figure it out and would appreciate some help. Also, as of right now my program only prompts the user for 6 inputs, but I'd like the user to be able to input as many as he/she would like to, any suggestions? I am pasting the code I currently have below.

import javax.swing.JOptionPane;
 
public class GPA_Calculation1_0 {
 
	public static void main(String[] args) {
 
String courseOne = JOptionPane.showInputDialog("Enter numeric GPA of Course One: ");//Course one
double numOne = Double.parseDouble(courseOne);
String courseTwo = JOptionPane.showInputDialog("Enter numeric GPA of Course Two: ");//Course two
double numTwo = Double.parseDouble(courseTwo);
String courseThree = JOptionPane.showInputDialog("Enter numeric GPA of Course Three: ");//Course three
double numThree = Double.parseDouble(courseThree);
String courseFour = JOptionPane.showInputDialog("Enter numeric GPA of Course Four: ");//Course four
double numFour = Double.parseDouble(courseFour);
String courseFive = JOptionPane.showInputDialog("Enter numeric GPA of Course Five: ");//Course five
double numFive = Double.parseDouble(courseFive);
String courseSix = JOptionPane.showInputDialog("Enter numeric GPA of Course Six: ");//Course six
double numSix = Double.parseDouble(courseSix);
 
 
 
double averageNum = ((numOne + numTwo + numThree + numFour + numFive + numSix)/6.0);
 
 
JOptionPane.showMessageDialog(null, "Your numeric GPA is: " + averageNum);//Displays output of calculation in dialog box
 
 
 
System.exit(0);
 
	}
 
}

Please edit your post and wrap your code with code tags:
[code=java]
YOUR CODE GOES HERE
[/code]
to get highlighting and preserve formatting.

Do you need to save the values?
Do you know about arrays? This is a good place to use them. (Later you'll learn about the ArrayList class which improves on arrays)
Using an array will require using a loop.

If you don't need to save the values, reuse the variable that the user enters his data into inside of a loop.