Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!mnetor!seismo!mcvax!inria!imag!lifia!fano
From: fano@lifia.UUCP
Newsgroups: comp.lang.c
Subject: help needed about dynamic space allocation
Message-ID: <1046@lifia.UUCP>
Date: Fri, 21-Nov-86 13:12:26 EST
Article-I.D.: lifia.1046
Posted: Fri Nov 21 13:12:26 1986
Date-Received: Sat, 22-Nov-86 06:46:39 EST
References: <13802@amdcad.UUCP> <359@prairie.UUCP>
Reply-To: fano@lifia.UUCP (Rampa*)
Organization: LIFIA-IMAG, Un. of Grenoble, France
Lines: 49

forgive the ignorance of a novice C-programmer:

I need advice on dynamic space allocation for multidimensionnal arrays:

Here is a way I have implemented dynamic allocation for a 2 X 2 matrix named
sig in a C-source file named combin1.c:
(I'll explain further the reason why I'm not satisfied with that solution)

  BEGINNING OF THE EXAMPLE:

  float **sig;                                    /* matrix declaration     */
  ....

  sig = (int *)malloc(n * sizeof(int));           /* allocates space for sig */
  for ( i = 0; i < n; i++)                        /* lines adresse           */
    {
      sig[i] = (float *)malloc(n * sizeof(float));/* allocates space for     */
    }                                             /* columns of line i       */
  ....

  for (i = n-1 ; i >= 0; i--)
    { 
      free(sig[i]);                                /* desallocates space     */
    }
  free(sig);

  END OF THE EXAMPLE


during the compiling time, I get the following warning:
     "combin1.c", line 220: warning: illegal pointer combination
any-way the program runs, and gives the desired results.


The compiler message suggests that I didn't use the proper way to implement
matrix dynamic allocation. So, could someone over there give me advices for
a cleaner solution.

Thanx.
-- 


    fano rampa*
///////////////////////////////////////////////////////////////////////////////

                           "Carmen lips are more exciting than Common lisp..."
                                                         -G.Bizet-

fano@lifia.UUCP      or     mcvax!lifia!fano