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From: ari@eleazar.dartmouth.edu (Ari Halberstadt)
Newsgroups: comp.lang.c
Subject: Re: Indefinite-length array as member of struct; sizeof(char)
Summary: Missing type cast and a question
Keywords: char string [] [0] [1]
Message-ID: <14474@dartvax.Dartmouth.EDU>
Date: 18 Jul 89 16:53:04 GMT
References: <7360@c3pe.UUCP> <821@fozzy.UUCP>
Sender: news@dartvax.Dartmouth.EDU
Reply-To: ari@eleazar.dartmouth.edu (Ari Halberstadt)
Organization: Dartmouth College, Hanover, NH
Lines: 34

I sent the following article, but it seems to have arrived without its
body [probably would have forgotten its head if it wasn't attached :-)].
I'm still new to the news networks, so I hope it doesn't appear twice.
The article follows:

In article <821@fozzy.UUCP> ellis@fozzy.UUCP (Randy Ellis) writes:
>In article <7360@c3pe.UUCP>, charles@c3pe.UUCP (Charles Green) writes:
>> When I know how long the string is I'm pushing onto the stack, I say:
>> 	nodeptr = malloc(strlen(data)+5);
>> to cover the struct node* and terminating NULL, and then simply
>> 	strcpy(nodeptr->string, data);
>
>Does this fit your needs?  Change string into a char pointer, then allocate
>dynamic memory for the string and save the pointer into nodeptr->string.
>	nodeptr = malloc(sizeof(struct node));
>	nodeptr->string = malloc(strlen(data)+1);
>	strcpy(nodeptr->string,data);

The sollution given by Randy Ellis is incomplete. Specifically, it omits
a type cast from type "char *" to type "struct node *". The correct line
should read:
	nodeptr = (struct node *) malloc(sizeof(struct node));

I also have a question about memory allocation. Are characters guaranteed
to be only one memory address long? This is very important in expressions
such as:
	nodeptr->string = malloc(strlen(data)+1);
Should the above line really be written as:
	nodeptr->string = malloc( (strlen(data)+1) * sizeof(char) );
I have seen the latter in several books, but it really wasn't clear from the
examples what should be done.

If possible, please include a source (e.g., book name) with your response.
Ari Halberstadt '91, "Long live short signatures"