Hi,

I have a giant string buffer, and I want to print out small chunks of it at
a time. How do I print out, say 20 characters of a string?

Is it like this?

printf("%20s",mystring);

I can change the start point of the string, I just don't know how to tell it
to only print out X number of characters from it.
Thanks
B

Bint said:

> Hi,
>
> I have a giant string buffer, and I want to print out small chunks of it
> at
> a time. How do I print out, say 20 characters of a string?
>
> Is it like this?
>
> printf("%20s",mystring);
>
> I can change the start point of the string, I just don't know how to tell
> it to only print out X number of characters from it.

printf("%.20s", mystring);

Note the dot in the format specifier.

Covered in K&R2 p244.

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

Bint wrote:
> Hi,
>
> I have a giant string buffer, and I want to print out small chunks of it at
> a time. How do I print out, say 20 characters of a string?
>
> Is it like this?
>
> printf("%20s",mystring);

printf("%.*s", len, mystring);


--
Tor <torust [at] online [dot] no>

C-FAQ: http://c-faq.com/

On Oct 17, 1:37 pm, "Bint" <b...@csgs.com> wrote:
> Hi,
>
> I have a giant string buffer, and I want to print out small chunks of it at
> a time. How do I print out, say 20 characters of a string?
>
> Is it like this?
>
> printf("%20s",mystring);
>
> I can change the start point of the string, I just don't know how to tell it
> to only print out X number of characters from it.
> Thanks
> B

Bint,

Another more flexible method would be to snprintf() your larger string
into a temporary string buffer and then output the temporary buffer
using a standard unformatted printf(). This will allow you to
dynamically change the size of your output string by supplying a
variable length for your temporary string buffer in the snprintf()
routine (which cannot be accomplished using the "%.20s" method
described by Richard.

Keith
http://www.doubleblackdesign.com

husterk said:

<snip>

> Another more flexible method would be to snprintf() your larger string
> into a temporary string buffer and then output the temporary buffer
> using a standard unformatted printf(). This will allow you to
> dynamically change the size of your output string by supplying a
> variable length for your temporary string buffer in the snprintf()
> routine (which cannot be accomplished using the "%.20s" method
> described by Richard.

There is really no need to go to all that trouble.

printf("%.*s\n", nchars, mystring);

Again, this is documented very clearly in K&R2.

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

"Richard Heathfield" <rjh@see.sig.invalid> a écrit dans le message de news:
CaOdnVqVmdolaYvaRVnyiwA@bt.com...
> husterk said:
>
> <snip>
>
>> Another more flexible method would be to snprintf() your larger string
>> into a temporary string buffer and then output the temporary buffer
>> using a standard unformatted printf(). This will allow you to
>> dynamically change the size of your output string by supplying a
>> variable length for your temporary string buffer in the snprintf()
>> routine (which cannot be accomplished using the "%.20s" method
>> described by Richard.
>
> There is really no need to go to all that trouble.
>
> printf("%.*s\n", nchars, mystring);
>
> Again, this is documented very clearly in K&R2.

Be careful to cast nchar as (int) if it has a different type, such as
size_t.

--
Chqrlie.