Write about Pointers & Structures?

We know that the name of an array stands for the add of its zeroth element. The same thing is true  of the names of a arrays of structure variables.

Suppose ‘product’ is an array variable of struct type. The name ‘product’ represents the address of its zeroth element.

Ex:– 

srtuct inventory

{

char name[20];

int no;

float price;

}

product [2],*ptr;

This statement declares product as an array of two elements, each of the type struct inventory and ptr as a pointer to data objects of the type struct inventory. The assignment

ptr=product;

Would assign the address of the zeroth element of product to ptr. i.e; the pointer ptr will now point to product[0]. It’s members can be accessed using the following notation.

ptr®name

ptr®no

ptr®price

the symbol ®is called the arrow operator (member selection operator) and is made up of a minus sign & a greater than sign.

When the pointer ptr is incremented by one, it is made to point to the next record, i.e., product[1].

The following for statement will print the values of members of all the elements of product array.      

      for(ptr=product;ptr<product+2;ptr++)

     printf(“%s%d%f\n”,ptr®name, ptr®no, ptr®price);

Ex:–Structure using pointers.

#include<stdio.h>

#include<conio.h>

main()

{

struct book

            {

            char name[20];

            char author[20];

            int id;

            };

struct book b₁={“C”, “swamy”, 100};

struct book *P;

P=&b1;

printf(“%s%s%d\n”,b1.name,b1.author, b1.id);

printf(“%s%s%d\n”, p®name, p®author, p®id);

getch();

}