'need help with textfiles (2)' Thread RSS Feed

need help with textfiles (2)

Mon, 18 Nov 2002 07:57:35 -0700

I have a text file which has some html constructs. I have to copy this text file into a new one but without any comments (ie. if there is <--hello-->, it has to be removed from the text file. How can I do that?

Re: need help with textfiles (2)

Mon, 18 Nov 2002 12:41:37 -0700

: I have a text file which has some html constructs. I have to copy this text file into a new one but without any comments (ie. if there is <--hello-->, it has to be removed from the text file. How can I do that?
:

Heres what I would do:

Have a boolean called InComment initially set to false.
Have a loop calling ReadLn to read the file line by line.
After reading the line have an if statement that does either:

1) If InComment is true, check for "-->". If it isnt found, ignore the whole string since its a comment. If it is found, delete all the text up to the "-->" and set InComment to false and write whats left of the string.

2) If InComment is false, check for "". If it is found, delete the text between the two sequences and write whats left of the string. If "-->" isnt found, set InComment to true and erase from " blah  blah  blah

And that should be all thats necessary. It was probably harder to try to describe the steps involved than it would have been to just write the pascal program, but I thought I would leave it to you to attempt first. If you still have problems just post what you have.

Re: need help with textfiles (2)

Tue, 19 Nov 2002 09:53:16 -0700

I tried doing what you told me but I didn't manage. Can you please send me the code so that i could know what I'm doing wrong please?

Re: need help with textfiles (2)

Tue, 19 Nov 2002 11:14:11 -0700

: I tried doing what you told me but I didn't manage. Can you please send me the code so that i could know what I'm doing wrong please?

It probably wont help much because I wrote it in a rush and it's incredibly messy, but this works fine here:

program a;

uses
  crt;

var
  inf, outf: text;
  s: string;
  comm: boolean = false;

begin
     assign(inf, 'comm.html');
     reset(inf);
     assign(outf, 'nocomm.html');
     rewrite(outf);

     while not eof(inf) do
     begin
          readln(inf, s);
          if (comm) and (pos('-->', s) = 0) then
             s := '';
          while (pos('<!--', s) > 0) or (pos('-->', s) > 0) do
          begin
               if (comm) then
               begin
                    if (pos('-->', s) > 0) then
                    begin
                         delete(s, 1, pos('-->', s) + 2);
                         comm := false;
                    end else
                    begin
                         s := '';
                    end;
               end else
               begin
                    if (pos('<!--', s) > 0) then
                    begin
                         if (pos('-->', s) > 0) then
                         begin
                              delete(s, pos('<!--', s), pos('-->', s) + 2 - pos('<!--', s) + 1);
                         end else
                         begin
                              delete(s, pos('<!--', s), length(s));
                              comm := true;
                         end;
                    end;
               end;
          end;
          if (s <> '') then
             writeln(outf, s);
     end;

     close(inf);
     close(outf);
end.

Re: need help with textfiles (2)

Sat, 23 Nov 2002 07:09:04 -0700

This message was edited by Moderator at 2002-11-23 10:32:3

I did exactly what you told me but no luck....my program is crashing. Here is what i wrote in my program and also here's my textfile.

Test.PAS
------------------

Program Test;

var InFile, Outfile : Text;
    Line : string;
    Command : boolean;


begin
  {Prepare file for input and output}
  Assign(InFile, 'C:\sample.HTM');
  Reset(InFile);                  {Open InFile for input}

  Assign(OutFile, 'C:\copy.HTM');
  Rewrite(OutFile);               {Open Outfile for output}

  {Copy the data line by line}
  while not EOF(InFile) do
    begin
    Command := False;
      ReadLn(InFile, Line);
      if Command and (pos('-->', Line) = 0) then
        Line := '';
      while (pos('<--', Line) > 0) or (pos('-->', Line) > 0) do
        begin
          if Command then
          begin
            if (pos('-->', Line) > 0) then
              begin
                delete(Line, 1, pos('-->', Line) + 2);
                Command := False;
              end;
          end;
        end;
    end;
    if (Line <> '') then
      WriteLn(OutFile, Line);

  {Close file}
  Close(InFile);
  Close(OutFile)
End.

Sample.HTM
--------------------------
<?html version="1.0">
<-- this is a comment -->
<scene>
<viewpoint from="0 0 -1" at="0 0 5" up="0 1 0"/>
<surface>
<sphere centre="0 0 5" radius="2"/>
<texture name="shiny_red"/>
</sphere>
</surface>

<light from="5 5 5"/>
</scene>

<-- This is a comment -->
viewpoint
{
from <0,0,-1>
at <0,0,5>
up <0,1,0>
}

object
{
sphere <0,0,5>,2
shiny_red
}

light <5,5,5>

Re: need help with textfiles (2)

Sat, 23 Nov 2002 10:35:34 -0700

This message was edited by Moderator at 2002-11-23 10:39:30

: I did exactly what you told me but no luck....my program is crashing. Here is what i wrote in my program and also here's my textfile.

You didnt do exactly what I told you, you cut out over half of the program. Without knowing what error message you are getting I wont know what is causing the crash, but even if you fix the crash I can tell you that what you have there will not work at all.

Actually I just looked at the code again...from what I can see the program shouldnt crash, but it definitely will be thrown into an infinite loop. My suggestion would be to either use my code in its entirety since I know for a fact it'll work, or to read through and fully understand the logic of it before you cut parts out. That's where your problem lies.