Problem with realloc

From: Daniel Chirillo (danchirillo_at_yahoo.com)
Date: 08/05/04 

Date: Wed, 04 Aug 2004 22:45:25 GMT

I'm playing around with dynamic arrays of strings. Can anyone offer an
explanation as to why the realloc in this code is crashing the program? For
now, ignore the fact that I'm leaking memory.

const int MAX_STR_LENGTH = 256;
char **array = (char **)malloc( sizeof(char*) * 1);
char *input = (char*)malloc(MAX_STR_LENGTH * sizeof(char));

 size_t length = -1;
 int i;

 while(-1) {

       length++;
       printf("Enter: ");
       scanf("%s", input);

       if( strcmp( "-1", input) == 0 ) break;
       array = (char **)realloc(array, length); /* the problematic line */

       array[length] = (char*)malloc(MAX_STR_LENGTH + 1);

       strcpy( array[length], input);

  }

  for(i = 0; i < length; ++i ) {
      printf("%s\n", array[i]);
  }

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