[prog] Strings in C

[Sue Stones]

below are some quick comments that are hopefully aproximatly correct!

On Fri, 18 Oct 2002 19:02, Therese Gustafsson wrote:
> Hi!
>
> I'm trying to write a C-program that accesses a
> postgresql-database. I'm having trouble with the
> stringhandling and I'm hoping someone here can help
> me.
>
> I have a short code-example and I'm going to try to
> explain what my problem is.
>
> Here are my variables:
> char email[256],l_email[40];
> int email_length;
>

you could put in a loop here to initialse the string to blanks, or nulls or 
whatever you want.  Something like this..
for (i=0; i<email_len; i++)
 l-email[i] = ' ';

(whatever the right variales are)



> This is where the user input is read in.
> printf("Input email-address: ");
> fgets(email, 256, stdin);
>
> Now here comes my problem. The email field in the
> database is only 40 characters long, so now I want to
> make sure that the email string is max 40 characters
> long and I don't want the "\0"-character at the end of
> the string.
>
> Here's what I've done. I get the length of the string
> the user input with strlen. (I don't understand why I
> have to subtract one, but if I don't the stringlength
> is one character to long. I thought strlen didn't
> count the "\0"-character?) Then if the length of the

Usually this is because things are numberd from zero, so teh length is one 
more than the value of the index.

> user input is longer than the field in the database I
> just truncate it.
> email_length = strlen(email)-1;
> if (email_length > 40)
> {
>         email_length = 40;
> }
>
> Now I copy the user input to another string that's as
> long as the field in the database. This is to copy all
> user input except for the "\0".
> strncpy(l_email,email,email_length);
>
> Problem number 1: If the string the user wrote is less
> then 40 characters the end of the l_email string
> sometimes contains "junk"-characters. How can I get
> rid of those? I want the rest of the string empty.
>
> Problem number 2: Isn't there an easier way to do
> this? It seems as if I've made it to complicated.

I don't know the answer to this one!
sue


> I'm sorry if I haven't explained it so you can
> understand. English isn't my first language.
>
> /Therese
>
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