I've been learning C for about two days now, and am a bit puzzled by a
couple of things to do with scanf:

Firstly, if I get a string from scanf, and the input contains a space, it
seems to cut the rest of the input off when I try to display the string with
printf.
For example:

Tell me your name
John Doe
Hello John

The code I'm using is:

#include <stdio.h>

void main()
{
char name[20];
printf("Tell me your name\n");
scanf("%s",&name);
printf("Hello %s\n",name);

scanf("%s",name);

Which I understood to be a bit of a mistake, as it's telling scanf to send
the input to a variable, rather than a pointer to a variable.  Is that ever
valid with scanf?  Compiler doesn't seem to like it much.

Am using lccwin on NT4.  Only writing command line programs for now.

TIA,

Short version: Use fgets() with stdin as the file instead.

Long version:

Pointer to char may have a different representation to other pointers.
Passing in name (without the &) is correct.

Remember, giving the name of an array yields a pointer to the first
memmber.

As for your other problem, of the scanning stopping at spaces. Use
fgets() instead. You get a whole line, or as far as the space you
have allocated.

I would tell you the correct format to pass into scanf to do
what you want, but I don't know it, and fgets is better anyway.

http://www.eskimo.com/~scs/C-faq/q12.17.html
http://www.eskimo.com/~scs/C-faq/q12.19.html
http://www.eskimo.com/~scs/C-faq/q12.20.html

http://www.eskimo.com/~scs/C-faq/q11.12.html
http://www.eskimo.com/~scs/C-faq/q11.14.html
http://www.eskimo.com/~scs/C-faq/q11.15.html

http://www.eskimo.com/~scs/C-faq/q6.3.html
http://www.eskimo.com/~scs/C-faq/q6.4.html
http://www.eskimo.com/~scs/C-faq/q6.8.html
http://www.eskimo.com/~scs/C-faq/q6.9.html
http://www.eskimo.com/~scs/C-faq/q6.12.html

http://www.eskimo.com/~scs/C-faq/top.html

It has lots of frequently asked/answered questions. :)

--
386

scanf is a lot harder than it looks, isn't it?

int main(void)

  return 0;

(Some clueful people here disagree with my opinion of scanf, by the way,
and you should give some consideration to their views rather than just
accepting blindly what I say about it.)

http://users.powernet.co.uk/eton/clc/cbooks.html has a list of books
which are generally considered non-sucking by most denizens of this
newsgroup. "C For Dummies" is *not* on that list.

        name

is the same as saying

        &name

or
        &name[0]

These articles might be of interest (among others):

--
386

Just wanted to say thanks to everyone for the help.  I've had a look at some
of the FAQs, and have been told by a friend never to use scanf - so I guess
fgets() will do nicely as a replacement.

Thanks again,

--
386

: Firstly, if I get a string from scanf, and the input contains a space, it
: seems to cut the rest of the input off when I try to display the string with
: printf.
: For example:

: Tell me your name
: John Doe
: Hello John

Thats because scanf() uses whitespace as a field delimiter.  It is
best to not use scanf().  Many comp.lang.c posters recommend using a
combination of fgets() and sscanf().  Check out the comp.lang.c FAQ
especially question 12.20 and related questions.

: The code I'm using is:

: #include <stdio.h>

: void main()
main() is defined to return an 'int'.  Proper declarations for main()
are:
1)  int main( void )  /* doesn't take command line arguments */
2a) int main( int argc, char **argv )  /* takes command line arguments */
2b) int main( int argc, char *argv[] ) /* equivalent to 2a above */

: Secondly, and don't laugh at this: in "C For Dummies", several of the
: lessons and examples contain statements like this:

Don't use "C for Dummies"  (you are not a dummy, use a book which a)
respects your intelligence, and b) provides accurate information).
Regular posters to this group will be more than happy to provide you
with titles of decent C programming books.  Just ask.

Paul

char format[80];

if( 0 > snprintf(format, sizeof format, "%%%d[^\n]", sizeof name - 1)) {
  puts("Can't construct Format-String for scanf call");
  exit(1);

Note: snprintf() is new in C99 and probably not available on
your system/compiler.