Having a bit of problem understanding why I am getting a
Segmentation fault here
I know it has something to do with my loop printing the
reverse of the message array input in first for-loop code

What is it I am not seeing???

Code:
#include <stdio.h>

#define LENGTH 100    /*  maximum length of message array   */

main()

{                            /******************************/
   char message[LENGTH];     /* declare all variables     */
   char *ptr;


   /*************************************************/
   /* this loop stores message in array with pointer*/
   /*     pointing to it's elements                 */ 
   /*************************************************/

   printf("Enter your message :  \n\n");
   for (ptr = (message -1) ; (*ptr = getchar()) != '\n' ; ptr++)  {
     ;
     ptr = "\0";        /*  sets pointer to NULL   */
   }

   printf("\n");

   /***********************************************/
   /*  this loop take message array and prints    */  
   /*   in reverse using decrementation of pointer*/
   /***********************************************/

    printf("Here's your message in reverse:  \n\n");
    for ( ptr ; ptr >= message; ptr--){
      putchar(*ptr);
    }

    printf("\n\n");

    return 0;

}