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-   -   Help! (http://www.programmingforums.org/showthread.php?t=855)

Darren Oct 14th, 2004 4:05 AM

i done this program,but when i execute the program,computer will display
"Exception in thread" main"java.lang.NosuchMethodError:main"
y ah? any 1 can help me??

Below are my coding

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Project extends JApplet implements ActionListener
{
CheckboxGroup p = new CheckboxGroup();
Checkbox NONE = new Checkbox("NONE",p,true);
Checkbox LAN1001 = new Checkbox("LAN1001",p,false);
Checkbox LAN1003 = new Checkbox("LAN1003",p,false);
Checkbox LAN1005 = new Checkbox("LAN1005",p,false);
JTextField name, icno, csc230, csc231, csc239, mgt227, enl205,
result1, result2, result3, result4, lan1;
JButton Calculatebutton;
public void init()
{
Container container= getContentPane();
JLabel data1Label= new JLabel ("BMS SEM1");
JLabel space2Label= new JLabel ("");
JLabel dataLabel= new JLabel (" Please enter your marks to get your grade:");
JLabel spaceLabel = new JLabel ("");
JLabel nameLabel= new JLabel ("Student name");
JLabel icnoLabel = new JLabel ("ICNO");
JLabel space1Label= new JLabel ("");
JLabel csc230Label= new JLabel ("CSC230");
JLabel csc231Label= new JLabel ("CSC231");
JLabel csc239Label= new JLabel ("CSC239");
JLabel mgt227Label= new JLabel ("MGT227");
JLabel enl205Label= new JLabel ("ENL205");
JLabel spaceLabel2= new JLabel (" ");
JLabel info= new JLabel ("if you are not taking please enter 0 in the textbar:");
JLabel spaceLabel1= new JLabel ("");

name= new JTextField (20);
icno= new JTextField (20);
csc230= new JTextField (7);
csc231= new JTextField (7);
csc239= new JTextField (7);
mgt227= new JTextField (7);
enl205= new JTextField (7);
result1= new JTextField (75);
result2= new JTextField (75);
result3= new JTextField (75);
result4= new JTextField (75);
lan1= new JTextField (7);
Calculatebutton= new JButton ("Enter");
container.setLayout (new FlowLayout (FlowLayout.LEFT));
container.add (data1Label);
container.add (space2Label);
container.add (dataLabel);
container.add (spaceLabel);
container.add (nameLabel);
container.add (name);
container.add (icnoLabel);
container.add (icno);
container.add (space1Label);
container.add (csc230Label);
container.add (csc230);
container.add (csc231Label);
container.add (csc231);
container.add (csc239Label);
container.add (csc239);
container.add (mgt227Label);
container.add (mgt227);
container.add (enl205Label);
container.add (enl205);
container.add (spaceLabel2);
container.add (info);
container.add (spaceLabel1);
container.add (NONE);
container.add (LAN1001);
container.add (LAN1003);
container.add (LAN1005);
container.add (lan1);
container.add (result1);
result1.setEditable (false);
container.add (result2);
result2.setEditable (false);
container.add (result3);
result3.setEditable (false);
container.add (result4);
result4.setEditable (false);


Calculatebutton.addActionListener (this);
container.add (Calculatebutton);
}

public void actionPerformed (ActionEvent e)
{
String g1, g2, g3, g4, g5, ag, lann1;
float avg, total;
float a =Integer.parseInt (csc230.getText());
float b =Integer.parseInt (csc231.getText());
float c =Integer.parseInt (csc239.getText());
float d =Integer.parseInt (mgt227.getText());
float x =Integer.parseInt (enl205.getText());
float la1=Integer.parseInt (lan1.getText());
String y = icno.getText();
String z = name.getText();

if(a<=100 && a>70)
g1 = "A";
else if(a<=69 && a>50)
g1 = "B";
else if(a<=50 && a>40)
g1 = "C";
else
g1 = "D";

if(b<=100 && b>70)
g2 = "A";
else if(b<=69 && b>50)
g2 = "B";
else if(b<=50 && b>40)
g2 = "C";
else
g2 = "D";

if(c<=100 && c>70)
g3 = "A";
else if(c<=69 && c>50)
g3 = "B";
else if(c<=50 && c>40)
g3 = "C";
else
g3 = "D";

if(d<=100 && d>70)
g4 = "A";
else if(d<=69 && d>50)
g4 = "B";
else if(d<=50 && d>40)
g4 = "C";
else
g4 = "D";

if(x<=100 && x>70)
g5 = "A";
else if(x<=69 && x>50)
g5 = "B";
else if(x<=50 && x>40)
g5 = "C";
else
g5 = "D";

total = a + b + c + d + x;
avg = total / 5;

if(avg<=100 && avg>70)
ag = "A";
else if(avg<=69 && avg>50)
ag = "B";
else if(avg<=50 && avg>40)
ag = "C";
else
ag = "D";


if(la1<=100 && la1>70)
lann1 = "A";
else if(la1<=69 && la1>50)
lann1 = "B";
else if(la1<=50 && la1>40)
lann1 = "C";
else
lann1 = "D";





Object Source=e.getSource();
if (e.getSource()==Calculatebutton)
{

result1.setText ("Your name is "+z+", your ic number is "+y);
result2.setText (" your CSC230 grade is " +g1+", CSC231 grade is "+g2+", CSC239 grade is "+g3+", MGT227 grade is "+g4+", and ENL205 grade is "+g5);
result3.setText (" your total marks of all subjects is " +total+ " your average mark is " +avg+ " and your average grade is " +ag);
Checkbox cb = p.getSelectedCheckbox();
String mode = cb.getLabel();
if(mode.equals("NONE"))
result4.setText("you don't have taken LAN subject in this semester");
else if(mode.equals("LAN1001"))
result4.setText("you are taking LAN1001 and your grade is "+lann1);
else if(mode.equals("LAN1003"))
result4.setText("you are taking LAN1003 and your grade is "+lann1);
else if(mode.equals("LAN1005"))
result4.setText("you are taking LAN1005 and your grade is "+lann1);
}
}
}

Berto Oct 14th, 2004 4:32 AM

You need a main method

public stactic void main (str args[]); <--- soemthing like that cant remember, otherwise the program does not no where to start from.

Mjordan2nd Oct 14th, 2004 6:47 AM

Or try viewing from AppletViewer.

Infinite Recursion Oct 14th, 2004 10:08 AM

Yes. A main function is required.

BoeMan Oct 15th, 2004 8:03 PM

In a program like this that acts as your "main" or primary method. You need a statement that denotes a main method like, "public static void main (String []args)"... good luck

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Project extends JApplet implements ActionListener
{
//INSERT IT HERE
public static void main (String [] args)
//INSERT IT HERE
{
CheckboxGroup p = new CheckboxGroup();

Darren Oct 17th, 2004 12:00 PM

still have error leh??
Does anyone have try to copy and execute my coding??

Darren Oct 17th, 2004 12:07 PM

i add

public static void main(String args[])
{
//create instance of Frame
Project myframe = new Project( );
myframe.addWindowListener(
new WindowAdapter( ) {
public void windowClosing(WindowEvent e)
{
System.exit(0);
}//end of windowclosing method
}
);
}



but still canot

BoeMan Oct 17th, 2004 7:35 PM

Hmmm, I am a complete java newb and am just taking my first programming class but... are you calling any methods in your programs from other java class programs? If so, make sure that you have them compiled first before trying to compile this beast.

good luck sir

Darren Oct 18th, 2004 12:28 AM

no wow,i din call any method
my coding just dun have a main class
so i try to add in
but still cannot
y??
help help
urgent

BoeMan Oct 18th, 2004 1:31 AM

what are you using to code in? if you are using an IDE what error message are you recieving? get textpad and compile it in there, then see what error message you get.
I just fought with a java program for 5 hours, it was very frustrating but once it worked it was very rewarding. stay at it, you will get it.

public class Project extends JApplet implements ActionListener

drop the "extends ...." to the second line, then compile

public class Project
xtends JApplet implements ActionListener
then be sure the file name is Project.java

seemed to compile fine for me
good luck


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