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From: tim@proton.amd.com (Tim Olson)
Newsgroups: comp.lang.c
Subject: Re: print % in c
Message-ID: <1991Feb27.020629.24624@dvorak.amd.com>
Date: 27 Feb 91 02:06:29 GMT
References: <61516@eerie.acsu.Buffalo.EDU> <31530035@hpcvia.CV.HP.COM>
Sender: usenet@dvorak.amd.com (Usenet News)
Reply-To: tim@amd.com (Tim Olson)
Organization: Advanced Micro Devices, Austin, TX
Lines: 32

In article <31530035@hpcvia.CV.HP.COM> brianh@hpcvia.CV.HP.COM (brian_helterline) writes:
| haozhou@acsu.buffalo.edu (Hao Zhou) writes:
| >since % and \ are recognized as special characters in printf, how do
| >you print out such kind special chars using printf?
| 
| Any character following a \ will be taken literally so just preceed
| any "special" char with a \ so:
| 
| 	printf( "This is a slash \\ and a precent sign \%\n" )
| 
| would produce: This is a slash \ and a percent sign %

No, it would produce: This is a slash \ and a percent sign
				     [note missing % !!!]  ^

The real answer is that '\' is a special escape character for
character constants and strings in C, and it is processed at
compile/assemble time.  It can be used to represent frequently used
values (e.g. \t = tab, \r = return, \n = newline, \\ = \), as well any
character by following the backslash with an octal constant.

printf(), on the other hand, uses '%' as its escape character, and
interprets it at runtime.  To get printf to print a '%' character, you
need to escape it with another %:

	printf("This is a percent sign: %%\n");


--
	-- Tim Olson
	Advanced Micro Devices
	(tim@amd.com)