Dharshana Eswaran am Dienstag, 2. Januar 2007 08:02:
> Hi All,
Hi Dharshana Eswaran
> I have a piece of code which reads as shown below:
>
> unless (open(IN, "in.txt")) {
> die("Cannot open input file \n");
> }
> binmode(IN);
>
> unless (open(OUT, "+>output.txt")) {
> die("Cannot open input file input.txt\n");
> }
>
> %structure = ( 1 => "A", 2 => "B", 3 => "C",
> );
> @keys = keys %structure;
> %table = ( A => 4, B => 8, C => 32,
> );
> $j=0;
>
> print("ENTER THE SEQUENCE between[1-3]:\n");
> $seq = <STDIN>;
> chop($seq);
> @seq = split(/ +/, $seq);
> $seq_len = @seq;
>
> $input = <IN>;
> @input = split(/ +/, $input);
> $new = join ("", @input);
>
> for($i=0; $i<$seq_len; $i++) {
> $read1[$i] = $table{$structure{$seq[$j]}};
> syswrite (OUT, $new, $read1[$i]);
> print OUT ("\n");
> $j++;
> }
>
> In the above code, i m trying to read the input in bytes and display them
> in another output file. The reading is done in different sizes (4 or 8 or
> 32bytes), as per the sequence specifed by the User. The input file with
> filehandle IN contains data as shown below:
>
> F1 2F 8A 02 05 09 00 00 00 04 2B 48 00 00 00 68
>
>
> When i use syswrite function, i face the following problem
>
> syswrite (OUT, $new, 4); => Writes 4 bytes properly
> syswrite (OUT, $new, $val); (where $val =4;) => Writes 4 bytes properly
> syswrite (OUT, $new, $read1[$i]); => This does not work. It displays all
> the bytes together, without seperators(new line). I dont know the reason.
>
> Can anyone please guide me in this?
My tip is that you start your code (always) with the two lines
use strict;
use warnings;
and define all your variables. You will get warnings like this for the line
above the syswrite line:
Use of uninitialized value in hash element at XXX line YYY.
Then you can inspect the values in $seq[$j] (with a warn statement), and
you'll see what's going wrong :-)
There are also missing checks for open, close, and syswrite; the second die
statement is misleading; most double quotes can be replaced by single quotes
because nothing is interpolated into the strings; some constructs can be
simplified and expressed in a shorter way; some statements are "old style"
perl.
How about modifying the code and reposting it when it does what you want?
Happy new year
Dani
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