On 1/3/07, John W. Krahn <[EMAIL PROTECTED]> wrote:
Dharshana Eswaran wrote:
> Hi All,
Hello,
> I have a piece of code which reads as shown below:
>
> unless (open(IN, "in.txt")) {
> die("Cannot open input file \n");
You should include the $! variable in the error message so you know *why*
it
failed.
> }
> binmode(IN);
You appear to be reading from a text file so why binmode?
> unless (open(OUT, "+>output.txt")) {
> die("Cannot open input file input.txt\n");
You should include the $! variable in the error message so you know *why*
it
failed.
> }
>
> %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);
You should use chomp() instead of chop().
> @seq = split(/ +/, $seq);
> $seq_len = @seq;
>
> $input = <IN>;
> @input = split(/ +/, $input);
> $new = join ("", @input);
Why not just modify the string instead of splitting and joining:
( my $new = <IN> ) =~ s/ +//g;
> for($i=0; $i<$seq_len; $i++) {
> $read1[$i] = $table{$structure{$seq[$j]}};
> syswrite (OUT, $new, $read1[$i]);
> print OUT ("\n");
perldoc -f syswrite
syswrite FILEHANDLE,SCALAR,LENGTH,OFFSET
syswrite FILEHANDLE,SCALAR,LENGTH
syswrite FILEHANDLE,SCALAR
Attempts to write LENGTH bytes of data from variable SCALAR to
the
specified FILEHANDLE, using the system call write(2). If
LENGTH
is not specified, writes whole SCALAR. It bypasses buffered
IO,
^^^^^^^^^^^^^^^^^^^^^^^^
so mixing this with reads (other than sysread()), "print",
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
"write", "seek", "tell", or "eof" may cause confusion because
the
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
perlio and stdio layers usually buffers data. Returns the
number
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
of bytes actually written, or "undef" if there was an error
(in
this case the errno variable $! is also set). If the LENGTH
is
greater than the available data in the SCALAR after the
OFFSET,
only as much data as is available will be written.
You are using syswrite() *and* print() on the same filehandle which you
shouldn't do.
> $j++;
> }
>
> In the above code, i m trying to read the input in bytes
It *looks* like you are reading lines of text?
> 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?
When I run your code it seems to work for me, so what exactly is not
working?
John
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Hi John,
Thanks for the suggestions regarding the code. I still need to learn to
optimize the code.
When I run your code it seems to work for me, so what exactly is not
working?
The output what i m getting is
The input file contains message as follows:
D0 1A 81 03 01 21 80 82 02 81 02 8D 0F 04 54 6F 6F 6C 6B 69 74 20 54 65 73
Sample output:
ENTER THE SEQUENCE between[1-3]:
2 1 1 3
The output file contains:
D01A8103012180820281028D0F04546F
I am unable to give spaces between each entry in the output.I need the
output in steps...
Something like:
D01A8103
0121
8082
0281028D0F04546F
I tried printing a new line after the syswrite instruction, but i am unable
to achieve that :-(
Thanks and Regards,
Dharshana
