Groups > comp.lang.java.programmer > #28262

Re: Problem with for

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From	Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: Problem with for
Date	Sun, 27 Apr 2014 14:04:25 -0400
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On 4/27/2014 1:55 PM, Venom Lust wrote:
>      public void writeText(String text)
>      {
>          char tmpchar;
>          int a = text.length();
>          for(int i = 0 ; i < text.length();i++);

     The `for' statement executes its subordinate statement multiple
(usually) times.  That subordinate statement is usually a {}-enclosed
block, but can be a simple statement.  What you've written is a `for'
whose subordinate statement is just `;', the empty statement.  So,
your code will execute `;' once for each `i' value, then forget all
about `i' and move ahead to the statement after the `for' ...

>          {
>              jTextArea1.setText(jTextArea1.getText() + text.charAt(i));
>              try {
>                  Thread.sleep(500);
>              } catch (InterruptedException ex) {
>                  Logger.getLogger(IJFMain.class.getName()).log(Level.SEVERE, null, ex);
>              }
>          }

... which happens to be a {}-enclosed block. But this block has nothing
to do with the `for', and is just a stand-alone bunch of code.  The code
refers to a variable named `i', but there's no such variable -- there
once was an `i' that was part of the `for', but the `for' is long gone.

>
> it says at text.charAt(i) that i doesnt exists and at for it says something like supress warning empty statement.
>
> anyone knows whats happening?

     Two things are happening. One, you don't know how to make a good
problem report: When you're puzzled by an error message, *quote* the
message and don't report "it says something like."

     Two, you've got a semicolon that you don't want.

-- 
Eric Sosman
esosman@comcast-dot-net.invalid

Thread

Problem with for Venom Lust <lucas__bertollo@hotmail.com> - 2014-04-27 10:55 -0700
  Re: Problem with for Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-04-27 14:04 -0400
    Re: Problem with for lipska the kat <lipskathekat@example.com> - 2014-04-27 20:07 +0100
      Re: Problem with for leif.roar@invalid.com (Leif Roar Moldskred) - 2014-04-27 15:56 -0500
  Re: Problem with for lipska the kat <lipskathekat@example.com> - 2014-04-27 19:15 +0100
    Re: Problem with for Venom Lust <lucas__bertollo@hotmail.com> - 2014-04-27 11:29 -0700
    Re: Problem with for Venom Lust <lucas__bertollo@hotmail.com> - 2014-04-27 11:31 -0700
    Re: Problem with for Venom Lust <lucas__bertollo@hotmail.com> - 2014-04-27 11:34 -0700
  Re: Problem with for Venom Lust <lucas__bertollo@hotmail.com> - 2014-04-27 11:17 -0700
  Re: Problem with for Roedy Green <see_website@mindprod.com.invalid> - 2014-04-27 16:22 -0700

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