Error in my simple program

Question

hey I'm a beginner to java and i tried to program a simple calculator but my Jcreator says it has an Error this is the program that i encoded:
import javax.swing.JOptionPane;
public class quiz
     public static void main(String[]args)
          String input;
          double quiz1,quiz2,quiz3,quiz4,quiz5,average;
          input=JOptionPane.showInputDialog("Enter first quiz:");
          Double.parseDouble(input);
          input=JOptionPane.showInputDialog("Enter second quiz:");
          Double.parseDouble(input);
          input=JOptionPane.showInputDialog("Enter third quiz:");
          Double.parseDouble(input);
          input=JOptionPane.showInputDialog("Enter fourth quiz:");
          Double.parseDouble(input);
          input=JOptionPane.showInputDialog("Enter fifth quiz:");
          Double.parseDouble(input);
          average=(quiz1+quiz2+quiz3+quiz4+quiz5)/5
          JOptionPane.showMessageDialog(null,"The average is" +average,"Average",JOptionPane.INFORMATION_MESSAGE);
          System.exit(0);
}

Answer 1

shouldn't it be like
input=JOptionPane.showInputDialog("Enter first quiz:");
if (input == null) {
            return;
quiz1 = Double.parseDouble(input); or something like that?
or else your "quiz" variable don't have any value?
Edited by: Billwaa on Dec 14, 2008 8:31 AM