There are three macros which I find indispensable and which I use in all my C projects, namely LEN, NEW and NEW_ARRAY. I keep them in a file named Util.h:

  #ifndef UTIL_H
  #define UTIL_H

  #include <errno.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>

  #define LEN(arr) (sizeof (arr) / sizeof (arr)[0])

  #define NEW_ARRAY(ptr, n) \
     (ptr) = malloc((n) * sizeof (ptr)[0]); \
     if ((ptr) == NULL) { \
        fprintf(stderr, "Memory allocation failed: %s\n", strerror(errno)); \
        exit(EXIT_FAILURE); \
     }

  #define NEW(ptr) NEW_ARRAY(ptr, 1)

  #endif

With these in place, working with arrays and dynamic memory is safer, less verbose and readability is improved.