Solved

stop the loop when enter nothing

Posted on 2001-06-18
6
195 Views
Last Modified: 2010-03-31
hai, i just need to implement a loop that can be stop when i enter "nothing"
by using the following incorrect statement:

  BufferedReader br=new BufferedReader(new InputStreamReader (System.in));
  do{
  System.out.print("Enter any string: ");
  String temp;
  temp=br.readLine();
  }while (br.readLine()!=null);
  //this loop is working wrongly,it doesn't stop!

output suppose to be like below:
Enter any string: abc
Enter any string: cds
Enter any string:
//when nothing(empty string) is being enter, the loop stop.

how the above coding can be modified?
0
Comment
Question by:JYnet
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 9

Expert Comment

by:Ovi
ID: 6205228
You will never be able to enter a null string. The readLine will wait until the enter caracter (at least) is entered. You have two solutions :
1. to provide an exit string (in my example "exit")
2. to implement a Timer which will count for an noumber of seconds and if nothing happends, force the exit from loop.

1.
import java.io.*;

public class x {
public static void main(String[] args) {
BufferedReader br=new BufferedReader(new InputStreamReader (System.in));
try {
  String line = null;
  System.out.print("Enter any string : ");
  while((line = br.readLine()) != null) {
    System.out.println("Entered : " + line);
    if(line.equalsIgnoreCase("exit"))
      break;
    System.out.print("Enter any string : ");
  }
} catch(Exception e) {System.out.println(e.toString());}
}
}
0
 

Accepted Solution

by:
Amarnath earned 5 total points
ID: 6205276
u can try in this way

BufferedReader br=new BufferedReader(new InputStreamReader (System.in));
               System.out.print("Enter any string: ");
               String temp = br.readLine();
               while(temp!=null && !temp.equals(""))
               {
                     System.out.print("Enter any string: ");
                     temp=br.readLine();
               }
0
 
LVL 3

Expert Comment

by:rjackman
ID: 6205394
try this 1
import java.io.*;

public class TestReader
{
     public static void main(String h[])
     {
          try
          {
          String temp = null;
          BufferedReader br=new BufferedReader(new InputStreamReader (System.in));
           do{
           System.out.print("Enter any string: ");
           
           temp=br.readLine();
          System.out.println("U Enter ------->"+temp);
          if(temp.length()==0)
               return;
           }while (temp!=null);
          }
          catch(IOException ioe)
          {
               ioe.printStackTrace();
          }

     }
}

cheers
RJ
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 3

Expert Comment

by:superschlonz
ID: 6206193
Another solution is:

String line;
while( (line = br.readLine()) != null )
{
  if( line.ttrim().length() == 0 )
    break;
  // process line here...
}
0
 
LVL 1

Expert Comment

by:scientist060700
ID: 6208721
put an if statement
if (br.readLine ()=null) {
system.exit(1);
}

OR

if (br.readLine()=null)
break;

this should work
--scientist
0
 

Author Comment

by:JYnet
ID: 6209091
thanks for providing solution, i will see which one is most efficient, thanks!
0

Featured Post

Revamp Your Training Process

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This was posted to the Netbeans forum a Feb, 2010 and I also sent it to Verisign. Who didn't help much in my struggles to get my application signed. ------------------------- Start The idea here is to target your cell phones with the correct…
In this post we will learn how to make Android Gesture Tutorial and give different functionality whenever a user Touch or Scroll android screen.
The viewer will learn how to implement Singleton Design Pattern in Java.
This tutorial explains how to use the VisualVM tool for the Java platform application. This video goes into detail on the Threads, Sampler, and Profiler tabs.

687 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question