typedef

                                    // Typedefs can also simplify definitions or declarations for structure pointer types. Consider this:

struct Node {
    int data;
    struct Node *nextptr;
};
// Using typedef, the above code can be rewritten like this:

typedef struct Node Node;

struct Node {
    int data;
    Node *nextptr;
};

                                    - Type Names The command typedef can be used to give a short name to a data
type. 
- For example, the name long long is long, so we can define a short name
ll
typedef long long ll;

                                    #include <stdio.h>
#include <string.h>
 
typedef struct Books {
   char title[50];
   char author[50];
   char subject[100];
   int book_id;
} Book;
 
int main( ) {

   Book book;
 
   strcpy( book.title, "C Programming");
   strcpy( book.author, "Nuha Ali"); 
   strcpy( book.subject, "C Programming Tutorial");
   book.book_id = 6495407;
 
   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);

   return 0;
}

                                    typedef int myint;

                                    typedef enum 
{
	false,
    true
}Bool;