Comments on: C in a Nutshell in a Nutshell

By: Of Braces and Semicolons | The Rebertian Times

Of Braces and Semicolons | The Rebertian Times — Sun, 24 Jan 2010 16:52:39 +0000

[...] up to the second part of this blog’s tagline by being about programming! (Well, there was C in a Nutshell2, but my point is it’s been a [...]

By: Chris Rebert

Chris Rebert — Wed, 06 Jan 2010 19:24:31 +0000

Yes, and in assembly language you get to know that definition quite well as you have to do the pointer arithmetic and dereferencing yourself (I recently took a class on assembly programming). I’ve now added this 3rd (and defining) array access method to the post.

Thanks for your comment; it means some people actually do read my blog :-)

By: Chris Rebert

Chris Rebert — Wed, 06 Jan 2010 19:15:06 +0000

Excellent point. I’ve now changed the example accordingly. Thanks!

By: Emre Guney

Emre Guney — Wed, 06 Jan 2010 14:03:20 +0000

Function-like macros: #define foo(a,b) a-b

Since macros are directly replaced in the code, they could be error-prone when used like functions. Therefore I strongly suggest using parenthesis in the macro definition to avoid errors due to operator precedence s.t.
#define foo(a,b) (a-b)
or in the following common case:
#define sq(a) ((a)*(a))

e.g. without parenthesis
foo(3,2)*5
expected:
5
got:
-7 (3-2*5)
sq(3-2)
expected:
1
got:
-5 (3-2*3-2)

By: Jeff McNeil

Jeff McNeil — Thu, 17 Dec 2009 21:57:04 +0000

I realize this is in response to an old post, but "index[array] ≡ array[index]" caught my eye. That's one of the odd trivia like interview questions I'll ask. It makes people stop and think what an array in C really is. There's actually another way of accessing an array element:

atl3itlt0350:~ jmcneil$ cat test.c
#include

int
main (int *argc, char *argv[])
{
   int num_array[] = {1,2,3,4,5};

   printf("Method One: %d\n", num_array[2]);
   printf("Method Two: %d\n", 2[num_array]);
   printf("Method Three: %d\n", *(num_array+2));

   return 0;
}
atl3itlt0350:~ jmcneil$ make test
cc     test.c   -o test
atl3itlt0350:~ jmcneil$ ./test
Method One: 3
Method Two: 3
Method Three: 3
atl3itlt0350:~ jmcneil$