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Internet Message Format | 1996-08-05 | 3.4 KB

Path: newshost.lanl.gov!tanmoy
From: [e-mail] (Tanmoy Bhattacharya)
Newsgroups: comp.lang.c
Subject: Re: Adding Arrays, anyone?
Date: 26 Jan 1996 15:38:03 GMT
Organization: Los Alamos National Laboratory
Distribution: world
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References: <[e-mail]>
    <[e-mail]>
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In-reply-to: [e-mail]'s message of Thu, 25 Jan 96 22:03:00 -0800

In article <[e-mail]>
[e-mail] (JACK GREENE) writes:
<snip>
   RK>  I tried something like
   RK>
   RK>  for(counter =0 ; counter != '\0'; counter++)
   RK>   printf("%c",string1[counter] + string2[counter]
   RK>
   RK>  and I got a bunch of garbage on the screen.

   :-) And I bet it didn't compile very well either :-)

Why do you say that? The missing ); is obviously a typo: is that what
you are talking about?

   When adding strings together like you've shown above, C will
   concatenate as opposed to doing the math that you're asking

What do you mean by concatenate in this context? I can't see any
concatenation going on there?

    it to do.  Try converting to  a numeric variable to
   add.  I would try something like this:

       for (counter = 0; counter != '0'; counter++) {
     printf("%c", itoa(
          atoi( string1[counter] ) +
          atoi(string2[counter]) )
     };

   The functions:
    atoi()   /* ascii to integer */
    itoa()   /* integer to ascii */

   are in the STDLIB.H in borlands cpp4.51

In every standard conforming compiler, <stdlib.h> has to declare
atoi. In no standard conforming compiler can it declare itoa.

atoi needs strings. I assume string1[counter] is a char, not a
string. atoi cannot be legally passed a char (or int that results from
the promotion of a char). Did you try your solution before posting?

Also, atoi can be used to interpret character strings as numbers even
on machines which do not use ascii.

   Of course somebody else might have it a little neater and I wouldn't
   mind seeing that either.
   The main idea is to convert the strings to integers.  You could even
   change the printf() to use
   "%d" and not even bother with the itoa().

Actually, I thought the question was of converting _characters_ to
integers: not strings to integers. A string is a sequence of
characters terminated by '\0', and it seemed the original poster
wanted a sequence of integers (not one integer) from a sequence of
characters.

In any case, as digits are guaranteed to be contiguous in any code
used by a C implementation, string1[counter]-'0' gives the int you
want (provided of course string1[counter] is between '0' and
'9'). Similarly, if x is any int between 0 and 9, '0'+x is the
corresponding character.

   Just a thought from an old BASIC and xBase hack learning C myself.

Happy hacking ...

Cheers
Tanmoy
--
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