How to create a loop that exits when I press enter twice?

[Candice Stewart]

i am trying to create a loop that exits when i press enter twice with blank lines. I've tried different methods but still can't think of a method that works. When this codes entered the input is saved to a file however i can't exit the loop no matter how many times i press enter with blank lines. help please.

private void run()
 
  {
 
    FileOutputStream outputStream;
    PrintWriter printWriter;
    String fileNam;
    String input;
 
    System.out.println("Creating new backupfile");
    System.out.println("Enter file name: ");
    fileNam = Genio.getString();
    System.out.println("Input: ");
    input = Genio.getString();
 
    try
 
    { 
 
        outputStream = new FileOutputStream(fileNam);
        printWriter = new PrintWriter(outputStream);  
 
      while(true)
         {
        printWriter.println(input);
 
        if(input.equals(""))
          {
          printWriter.flush();
          printWriter.close();
        }
 
      }
    }
 
    catch(Exception e)
 
    { System.out.println("File cannot be written to"); }
 
    System.out.println("backup finished");
 
    }
 

[Jose Diaz]

try '\0' or '\n' if equals those, or if NULL has being define you can say if equals NULL, i haven't written much in java but if you really need help then tell so i can work on it. =)

[Nepomuk]

Hi there!
It's a bit difficult to answer the question completely, as you didn't include the code defining and initializing the "Genio" object, but there are a few things you'll have to change.

1. You'll want to reread the input in that loop of yours, so better put the input = Genio.getString (); line inside the loop. The way it is, it's not reading whatever you type. Mind you, if "input" is just the name of the file, you'll have to create some kind of FileReader.
2. As your loop has the condition "true" (which is always true of course), you need a different way to get out of it. If you insist on keeping the loop that way, you will want to use a break command. Here's a quick example of how to use break:

   int i=0;
   while(true) {
      i++;
      println(i);
      if(i>100) break;
   }

   That will print the numbers 1 - 100 and then stop.
3. As you want it to stop if you press enter twice, you'll have to add code to remember if it's pressed once. For example you could do something like this:

   boolean pressedOnce = false;
   while(true) {
     /*
     put code for reading input here
     */
     if(input.equals("")) {
       if(pressedOnce)
         break;
       else
         pressedOnce = true;
      }
     else {
       pressedOnce = false; // leave this out, if you don't want to limit yourself to two empty lines directly after each other
       /*
       whatever you want to do if the input was not an empty line
       */
     }
   }

4. If you're not stuck with the while(true) thing, you could also do something more sophisticated, like this:

   boolean pressedOnce = false;
   while((input = Genio.getString) != "" || !pressedOnce) {
     if(input.equals("")) {
       /*
       similar to before
       */
     }
   }

   (Untested, but it should work something like that.)

OK, that's all I can think of right now.

Greetings,
Nepomuk