Re: Problem with for

From:
Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 27 Apr 2014 14:04:25 -0400
Message-ID:
<ljjgr9$143$1@dont-email.me>
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

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