C语言指向结构的指针

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

struct Books {
   char  Title[50];
   char  author[50];
   char  subject[100];
   int   book_ID;
};

/* function declaration */
voID printBook( struct Books *book );
int main( ) {

   struct Books Book1;        /* Declare Book1 of type Book */
   struct Books Book2;        /* Declare Book2 of type Book */

   /* book 1 specification */
   strcpy( Book1.Title, "C Programming");
   strcpy( Book1.author, "Nuha Ali"); 
   strcpy( Book1.subject, "C Programming Tutorial");
   Book1.book_ID = 6495407;

   /* book 2 specification */
   strcpy( Book2.Title, "Telecom Billing");
   strcpy( Book2.author, "Zara Ali");
   strcpy( Book2.subject, "Telecom Billing Tutorial");
   Book2.book_ID = 6495700;

   /* print Book1 info by passing address of Book1 */
   printBook( &Book1 );

   /* print Book2 info by passing address of Book2 */
   printBook( &Book2 );

   return 0;
}

voID printBook( struct Books *book ) {

   printf( "Book Title : %s\n", book->Title);
   printf( "Book author : %s\n", book->author);
   printf( "Book subject : %s\n", book->subject);
   printf( "Book book_ID : %d\n", book->book_ID);
}