Re: \n?? \r??

From: Drebin (thedrebin_at_hotmail.com)
Date: 09/17/04 

Date: Fri, 17 Sep 2004 16:29:34 GMT

Best. Explanation. Ever.

"James Curran" <JamesCurran@mvps.org> wrote in message
news:%23Iw82INnEHA.4080@TK2MSFTNGP10.phx.gbl...
> "Sarah" <Sarah@discussions.microsoft.com> wrote in message
> news:C4BEF541-4382-4659-AFE0-F0DC49A9A7C1@microsoft.com...
>
> > what's the difference between \n and \r
>
> To understand the characters, you need to know a little history.
> When the original ASCII standard was defined, computers used teletypes for
> interacting with users --- Video monitors were rare to nonexistent.
Moving
> to a new line was a two step process: you had to move the carriage (the
> thing stamping letters on the paper) back to the left margin, and you had
to
> advance the paper up one line. When the control codes were defined, it
was
> decided that these actions would be given separate codes, for more
flexible
> control over printing. For one thing, this allowed over- printing --
> returning the carriage without advance to paper, so the next line is
printed
> on top of the last. The most common use for this was to obscure a
password
> the user had to enter, so it couldn't be read by someone pulling an old
> listing out of the garbage. So, char 10 (0x0A) is defined as a "Line
Feed"
> (LF), and char 13 (0x0D) is defined as "carriage return" (CR)
>
> As CRT terminals started to be used, separate codes was less
important,
> but hard disk space was at a premium, so OS designer started to use the
> convention of using just one of the characters as an "End of Line" code.
> Most people used CR; UNIX, in their iconoclastic way, chose LF instead.
> When the C language was defined --- by Unix users --- they made LF the
"next
> line" character ('\n'), and throw in CR ('\r') as a sop to everyone else.
> (Those symbols were carried over to C++ & C#)
>
> Then in 1982, IBM announced it's PC, and, at the same time, finally
> decided to embrace ASCII (they had been using the very bizarre EBCDIC
> before), --- and really embraced it and actually required both CR LF
> characters as and end-of-line, as it said in the official ignored
standard.
> Most of the systems using just CR eventually converted to CR LF, or just
> faded away. Unix, on the other hand, continued using just LF.
>
> So, now (c1985) we have a programming language (C), producing files
with
> just a LF, and an operating system (MS-DOS) requiring CR LF. So, the
> authors of C Run-time library created the concept of "text mode" files,
> where, when reading files it would convert CR LF into LF, and when writing
> files it would convert LF to CR LF. (Similarly, this has been carried
over
> of C++'s iostreams & to the .Net CLR)
>
> --
> Truth,
> James Curran
> Home: www.noveltheory.com Work: www.njtheater.com
> Blog: www.honestillusion.com Day Job: www.partsearch.com
> (note new day job!)
>
>