C: Concatenation of multiple strings

[negru]

How to concat multiple strings in C?

I have a function for concat two strings:

char* concat(char *s1, char *s2)
{
  char *r, *t;
  int d1 = -1, d2 = -1;
  while (s1[++d1]);
  while (s2[++d2]);
  t = r = (char *)calloc(d1 + d2 + 1, sizeof(char));
  while (*t++ = *s1++);
  t--;
  while (*t++ = *s2++);
  return r;
}

Is there a way to use this function with two strings to implement with multiple strings?
For example, prototype is

char * concat(char **array, int n);

Also, is this dynamic allocation right:

char* concat(char** array, int n)
{
 char *r; int i;
   r=(char *)calloc(n*MAX+1, sizeof(char));
   array=(char **)malloc(n * sizeof(char *));
   for(i=0;i<n;i++)
   {
       array[i]=(char *)malloc(MAX+1);
   }

   //concatenation//

   free(r);
   free(array[i]);
   free(array);
 }

Thanks for replies.