Path: utzoo!utgpu!attcan!uunet!tektronix!reed!psu-cs!poek
From: poek@psu-cs.UUCP (Ken Poe)
Newsgroups: comp.lang.c
Subject: RE: total space of a string
Message-ID: <1431@psu-cs.UUCP>
Date: 30 Dec 88 00:45:23 GMT
Reply-To: poek@psu-cs.UUCP (Ken Poe)
Organization: Dept. of Computer Science, Portland State University; Portland OR
Lines: 59

In article <29@rpi.edu> > kyriazis@rpics (George Kyriazis) writes:

>In article <1827@solo11.cs.vu.nl> maart@cs.vu.nl (Maarten Litmaath) writes:
>>barmar@think.COM (Barry Margolin) writes:
>>\1) When I've done this in other languages, I've used something like
>>\strlen("/") instead of the 2.  Unfortunately, in C I'd still have to
>>\say "+1", ....
>>
>>How about the following?
>>
>>	sizeof "/"
>
>"/" is a pointer to a string containing a '/' and a '\0'.  Therefore
>it seems to me that sizeof "/" will return the same value as 
>sizeof( char * ).  
>Comments??

	Only if your system has 2 byte pointers.

	The sizeof operator in C returns the size of the object (or of 
	any object of that type for size of a type).  When the object 
	is a "string" (actually an array of char), the sizeof operator
	returns the number of bytes in the array. (including the null
	character ('\0') at the end of the "string") 

	Try the following:

		main()
		{
			static char string[] = "abcd";
			/* null char appended to string constants by the compiler */

			printf("The size of string is %d\n", sizeof(string) );
			printf("The size of \"/\" is %d\n", sizeof "/");
			printf("The size of (char *) is %d\n", sizeof (char *) );
		}

	On the VAX it's output is:

		The size of string is 5
		The size of "/" is 2
		The size of (char *) is 4

	The only thing that is implementation dependent is the size of
	a pointer (32 bits on most systems) which can be 2 bytes.  (near
	pointers in MSC etc).

-- 
   Kenneth N. Poe ATP, CFI  |  ARPANET: poek%cs.pdx.edu@relay.cs.net
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