newbie question...helppp plzz

[teena abraham]

im in the process of learning java. trying to write a small program. i wrote the methods. now i dont know how to invoke the methods in my main
here is the code

class test{
    
    public void do0_9(){
        for ( int i=0; i <9; i++){
            System.out.println(i);
        }
    }
    
    public void do0_99(){
        
        int i=9;
        
        while (i<100){
            
            System.out.println(i);
        }
    }
    
    public void do0_999(){
        
        int i=99;
        
        while (i<999){
            
            System.out.println(i);
        }
    }
    
    public static void  main(String[] args){
      
      int i = Integer.parseInt( args[0] );
        if ( i<10)
           //here i want to print the 1 to 9
           // return d0_9();
        else if ( firstVal <99)
            return d0_99();
        
        else if ( firstVal < 999)
            return d0_999();
    }
}

CAN ANYONE HELP ME.....THANKS IN ADVANCE
[ edited to preserve formatting using the [code] and [/code] UBB tags -ds ]
[ December 31, 2002: Message edited by: Dirk Schreckmann ]

[Avi Abrami]

Teena,
Method "main()" is a static method (since it is defined using the 'static' keyword). The other methods in your "test" class are instance methods (i.e. not static). In order to invoke an instance method, you need an instance. So, in my opinion, you have two choices:
1. make all the instance methods static methods
2. create an instance of class "test" in method "main()", example:-
test aTest = new test();
Then you can do the following:-
aTest.do0_9();
Hope this has helped you.
Good Luck,
Avi.

[Blake Minghelli]

Kind of off the subject, but your methods also have a bug:

 
public void do0_99(){ 
   int i=9;                
   while (i<100){
     System.out.println(i);        
   }    
}

Since your method does not increment i (e.g. i++), i will never reach 100 so your program will print "9" repeatedly - probably not what you intended.
[ December 31, 2002: Message edited by: Blake Minghelli ]

[teena abraham]

Thanks Avi and Blake
I made modifications according to ur sugegstions but im getting a runtime error..... :roll:
here is the code

import java.io.*;
import java.lang.Math;
import java.util.*;
 
class Empty{
    
    public void do0_9(){
        for ( int i=0; i <9; i++){
            System.out.println(i);
        }
    }
    
    public void do0_99(){
        
        int i=9;
        
        while (i<100){
            
            System.out.println(i);
        }
    }
    
    public void do0_999(){
        
        int i=99;
        
        while (i<999){
            System.out.println(i);
        }
    }
    
    static String result(){
        String   line;
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        try   {  
            line = in.readLine();
            return line;
        }
        catch (Exception e){
            return "error";
        }
    }
    
    public static void  main(String[] args)throws Exception{
       
        Empty test= new Empty();
        String check= result();
        int x = Integer.parseInt( check );
        if ( x<10)
            test.do0_9();  
        else if (x<99)
            test.do0_99();
        else if (x< 999)
            test.do0_999();   
    }
}

dont know where i went wrong....any help appreciated
[ edited to preserve formatting using the [code] and [/code] UBB tags -ds ]
[ December 31, 2002: Message edited by: Dirk Schreckmann ]

[Avi Abrami]

Teena,
I copied the code you posted here, compiled it and ran it -- and I didn't get a runtime error. I am using JDK 1.4.1_01 on Windows 2000.
However, you did not correct the mistakes that Blake pointed out, so when I execute the "Empty" class and supply a value greater than 9 (nine), I get an infinite loop!
Perhaps you would care to post the runtime error message (and accompanying stack trace) that you are getting?
Good Luck,
Avi.

[teena abraham]

Thanks avi for spending ur valuable time in teaching me the basics of java. stupid of me wat happened is i didnt give a number and pressed enter button.
actually i have changed the code wat Blake has pointed out. but i cut and pasted the pre version. but even then its going as an infinite loop

  import java.io.*;
    import java.lang.Math;
    import java.util.*;
class Emptytest{
    //int i;
    public void do0_9(){
        for ( int i=0; i <9; i++){
            System.out.println(i);}
    }
    public void do0_99(){
       for( int i=9;i< 99;i++){
        //while (i<100){
            System.out.println(i);}
    }

    public void do0_999(){
       for( int i=99;i<999; i++){
       //while (i<999){
            System.out.println(i);}
    }
     static String result(){
            String   line;
                BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
                try   {  line = in.readLine();
                       return line;
                       }
                catch (Exception e){
                 return "error";
                   }
        }

    public static void  main(String[] args)throws Exception{
       
  
              
        Empty test= new Empty();
        String check= result();
        
         int x = Integer.parseInt( check );
         if ( x<10)
         test.do0_9();  
    
        else if (x<100)
        test.do0_99();
         
       else if (x< 1000)
       test.do0_999();
    }
        }

(code tags added by Marilyn)
[ January 01, 2003: Message edited by: Marilyn de Queiroz ]

[Marilyn de Queiroz]

import java.io.*;
class Emptytest{
    public void do0_9(){
        for ( int i = 0; i < 9; i++ ){
            System.out.println( i );
        }
    }
    
    public void do0_99(){
       for( int i = 9; i < 99; i++ ){
            System.out.println( i );
        }
    }
    
    public void do0_999(){
        for( int i = 99 ; i < 999; i++ ){
            System.out.println( i );
        }
    }
    
    static String result(){
        String   line ;
        BufferedReader in = new BufferedReader( new InputStreamReader( System.in ));
        try   {  
            line = in.readLine();
            return line ;
        }
        catch ( Exception e ){
            return "error";
        }
    }
    
    
    public static void  main( String[] args )throws Exception{
        Emptytest test = new Emptytest();
        String check = result();
        
        int x = Integer.parseInt( check );
        if ( x < 10 )
        test.do0_9();  
    
        else if ( x < 100 )
        test.do0_99();
         
        else if ( x < 1000 )
        test.do0_999();
    }
}
  

[ January 01, 2003: Message edited by: Marilyn de Queiroz ]

[Marilyn de Queiroz]

but even then its going as an infinite loop

I don't see an infinite loop....

Perhaps you need to define what you want your program to do.

The current program does this:

Get input from keyboard
Parse it
if ( x < 10 ), print all numbers from zero to (but not including) 9
else if ( x < 100 ), print all numbers from zero to (but not including) 99
else if ( x < 1000 ), print all numbers from zero to (but not including) 999.

No infinite loop here.

[Robbie shi]

class test {
  public void do0_9() {
    for (int i = 0; i & lt; 9; i++) {
      System.out.println(i);
    }
  }
  
  public void do0_99() {
    int i = 9;
    while (i & lt;
      100
    ) {
      System.out.println(i);
    }
  }
  
  public void do0_999() {
    int i = 99;
    while (i & lt;
      999
    ) {
      System.out.println(i);
    }
  }
  
  public static void main(String[] args) {
    test t = new Test();
    int i = Integer.parseInt(args[0]);
    if (i & lt;
      10
    )t.do_9();
    else if (firstVal & lt;
      99
    )
    t.do_99();
    else if (firstVal & lt;
      999
    )
    t.do_999();
  }
 }

--
Robbies
-----------------------------
1.java IDE tool : JawaBeginer
2.Java Jar tool : JavaJar
http://www.pivotonic.com
-----------------------------
[ edited to add line breaks to code -ds ]
[ January 05, 2003: Message edited by: Dirk Schreckmann ]

[Divya Venkatesh]

Here is the working code.I have commented your mistakes in the code.I dont know if this is what you want.If u need any clarifications do ask.

 //u must have one public class which will be the name of the file
public class test{
    
//function starts here.    
public void do0_9(){
        for ( int i=0; i<9; i++){
            System.out.println(i);
        }
    }
//ends here.
    
//function starts here.
    public void do0_99(){        
int i=5;  
while (i<100){
            
            System.out.println(i);
// infinite loop.Will never ends and make the code
//crash.So add a counter
i++; 
        }
    }
//ends here.
//function starts here 
   public void do0_999(){
        
        int i=99;
        
        while (i<999){
            
            System.out.println(i);
// infinite loop.Will never ends and make the code
//crash.So add a counter
i++; 
        }
    }
//ends here.
    
    public static void  main(String[] args){
      //u have to instantiate this class since the methods are not Static and one cannot call a 
//non static method from a static context.
test t= new test();
// where is firstVal???I guess it is i.
      int i=5;
        if ( i<10)
{
           //here i want to print the 1 to 9
           // return d0_9();
   t.do0_99();
}
        else if ( i<99)
{
            t.do0_99();
        return;  
}        
        else if ( i< 999)
        {
                        t.do0_999();
                         return;
                }  
           
}
}
 

Hope you've got this clear.