STRUCTURE---

Definition:-

• Defining a structure means creating a new datatypes
• It gives a way to grouping a variable
• Structure is a collection of dissimilar elements while array is for similar 
• it can be defined outside or inside the function
• struct keyword is used for defining a structure  

Syntax: 

         struct variable_name

         {    declaration of member variable   };  

                                           at last ; semicolon insert 

Example:

  1)   struct date{     //define outside the function

        int d,m,y;  //member variable

        };   or }d2;  where d2 is the variable of structure

        main()

        {-------}

  2)   main()

       {

            struct date{     //define inside the function

            int d,m,y;

            };

          }

how to declare and initialize structure variable:

1) above d2 is declared

2) it is declared as other variable data_types variable _name; but it have struct keyword

main()

{

   struct date today;  // where date is data_type and today is variable

   today.d=26;

}

Explanation:- today is variable name of structure, in structure there is 3 memory d,m,y. i.e d,m,y  present in today, so in d of today(today.d it is required because the member variable doesn't have its own identity) assign =26.

Program:-

Explanation:-

1) scanf and gets both takes the input from buffer not directly from the user, if buffer is empty then come to user,

2)first buffer is empty scanf take the input from user bookid

3)now buffer is not empty so gets function cannot take input from user, but we use a fflush(stdin) function , which make user to give a input

4)all input is taken which is stored in b id,titile,price;

5)new variable is declared b1 which access the all b value, now b=b1

6)display the b1