grading program help

**devilhanzou** · February 13th, 2011, 07:15 PM

my code is supposed to calculate quiz 10% pratical 50 %, exam, and midterm 40 % and output overall average and quivalent letter grade.

import javax.swing.*;
import java.text.*;
 
public class c6gradecalculation
{
	private double q1;
	private double pa;
	private double mid;
	private double fin;
	private double q1score;
	private double pascore;
	private double midscore;
	private double finscore;
	private double overallscore;
 
public String grade;
public String myLetterGrade()
{
	String grade ="";
	if (overallscore <60)
		grade = "F";
	else if (overallscore >=60 && overallscore < 70)
		grade = "D";
	else if (overallscore >=70 && overallscore < 80)
		grade = "C";
	else if (overallscore >=80 && overallscore < 90)
		grade = "B";
	else if (overallscore >=90 && overallscore <=100)
		grade = "A";
	return grade;
}
 
public double getScore()
{
	q1 = Double.parseDouble(JOptionPane.showInputDialog("Enter Quiz Score (0-100)"));
	pa = Double.parseDouble(JOptionPane.showInputDialog("Enter Pratical Average Score (0-100)"));
	mid = Double.parseDouble(JOptionPane.showInputDialog("Enter Midterm Exam Score (0-100)"));
	fin = Double.parseDouble(JOptionPane.showInputDialog("Enter Finals Exam Score (0-100)"));
 
	q1score = q1 * 0.10;
	pascore = pa * 0.50;
	midscore = mid * 0.20;
	finscore = fin * 0.20;
 
	overallscore = (q1score + pascore + midscore + finscore);
	return overallscore;

**copeg** · February 13th, 2011, 07:59 PM

my code is supposed to calculate quiz 10% pratical 50 %, exam, and midterm 40 % and output overall average and quivalent letter grade.

And what is the problem? Does it compile? Are there exceptions? Does it misbehave? Providing as much detail as possible will help you get more meaningful suggestions faster.

**devilhanzou** · February 13th, 2011, 08:02 PM

i forgot to post my two ending brackets, but it compiles fine but does not run at all also not sure about the main everytime i put it in it does not work at all.

**javapenguin** · February 14th, 2011, 01:05 AM

Hmmmm...that's still not very informative.

I do find that you can do without

public String grade;

As for not running, you have neither a println nor a JOptionPane.

All the return is doing is returning a value from that method.

As you never do anything with any of your methods, it will terminate as soon as it starts.

Third, you lack a main method, which is required to run.

Otherwise you'll get an annoying "NoSuchMethodError "main".

I'd recommend doing this:

 
mport javax.swing.*;
import java.text.*;
 
public class c6gradecalculation
{
	private double q1;
	private double pa;
	private double mid;
	private double fin;
	private double q1score;
	private double pascore;
	private double midscore;
	private double finscore;
 
 
 
public String myLetterGrade(int overallscore)
{
	String grade ="";
	if (overallscore <60)
		grade = "F";
	else if (overallscore >=60 && overallscore < 70)
		grade = "D";
	else if (overallscore >=70 && overallscore < 80)
		grade = "C";
	else if (overallscore >=80 && overallscore < 90)
		grade = "B";
	else if (overallscore >=90 && overallscore <=100)
		grade = "A";
	return grade;
}
 
public double getScore()
{
	q1 = Double.parseDouble(JOptionPane.showInputDialog("Enter Quiz Score (0-100)"));
	pa = Double.parseDouble(JOptionPane.showInputDialog("Enter Pratical Average Score (0-100)"));
	mid = Double.parseDouble(JOptionPane.showInputDialog("Enter Midterm Exam Score (0-100)"));
	fin = Double.parseDouble(JOptionPane.showInputDialog("Enter Finals Exam Score (0-100)"));
 
	q1score = q1 * 0.10;
	pascore = pa * 0.50;
	midscore = mid * 0.20;
	finscore = fin * 0.20;
 
	overallscore = q1score + pascore + midscore + finscore;
	return overallscore;
}
 
public static void main(String[] args)
{
double ovScore = getScore();
 
JOptionPane.showMessageDialog(null, myLetterGrade(ovScore), "Your grade is: " , JOptionPane.INFORMATION_MESSAGE);
 
// you have set ovScore to the value returned by the getScore() method.  You then pass that value as a 
//  parameter to myLetterGrade method, which returns a String (the letter grade) which is outputted
// in the JOptionPane.  The last parameter in that JOptionPane is the message type.  The first is the 
// parent Component, usually null, and the third is the title.  The second is the message itself.
// All programs, minus applets, require a main method to actually run.  They can compile without a main
// (assuming all other code is correct), but they can't run. (Again, applets don't need a main and in fact get // mad if you have one I think.  But that's beside the point.)  
 
 
 
 
 
 
}
}

**devilhanzou** · February 14th, 2011, 07:30 AM

k thank you for the help. i feel asleep last night i had alot more java homework than this, it is just my final one so got brain dead and past out in front of pc.

but woke up to this code so going though it now i still do not totally understand the last part, but am going over it now

**devilhanzou** · February 14th, 2011, 07:41 AM

These are the errors i am getting now. I am beginning to undestand why the original code was not running. it had no main so it really was just the two seperate problems and nothing connecting them to each other

C:\Users\Michael\Documents\School stuff\c6gradecalculation1.java:45: cannot find symbol
symbol : variable overallscore
location: class c6gradecalculation1
overallscore = q1score + pascore + midscore + finscore;
^
C:\Users\Michael\Documents\School stuff\c6gradecalculation1.java:46: cannot find symbol
symbol : variable overallscore
location: class c6gradecalculation1
return overallscore;
^
C:\Users\Michael\Documents\School stuff\c6gradecalculation1.java:51: non-static method getScore() cannot be referenced from a static context
double ovScore = getScore();
^
C:\Users\Michael\Documents\School stuff\c6gradecalculation1.java:53: myLetterGrade(int) in c6gradecalculation1 cannot be applied to (double)
JOptionPane.showMessageDialog(null, myLetterGrade(ovScore), "Your grade is: " , JOptionPane.INFORMATION_MESSAGE);
^
4 errors

Tool completed with exit code 1

**BuhRock** · February 14th, 2011, 09:01 AM

You didn't pass the overallscore variable into the getScore method, so the compiler can't find it.

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