C++ LANGUAGE POINTERS TO STRUCTURES

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C++ LANGUAGE POINTERS TO STRUCTURES

Pointers to Structures 


You can define pointers to structures in very similar way 
as you define pointer to any other variable as follows: 

struct Books *struct_pointer; 

Now, you can store the address of a structure variable in 
the above defined pointer variable. To find the address of 
a structure variable, place the ‘&’ operator before the 
structure's name as follows: 

struct_pointer = &Book1; 

To access the members of a structure using a pointer 
to that structure, you must use the -> operator as follows: 

struct_pointer->title; 

Let us re-write above example using structure pointer, 
hope this will be easy for you to understand the concept:
 
#include <iostream> 
#include <cstring> 
  
using namespace std; 
void printBook( struct Books *book ); 
 
struct Books 
{ 
   char  title[50]; 
   char  author[50]; 
   char  subject[100]; 
   int   book_id; 
}; 
  
int main( ) 
{ 
   struct Books Book1;        // Declare Book1 of type Book 
   struct Books Book2;        // Declare Book2 of type Book 
  
   // Book 1 specification 
   strcpy( Book1.title, "Learn C++ Programming"); 
   strcpy( Book1.author, "Chand Miyan");  
   strcpy( Book1.subject, "C++ Programming"); 
   Book1.book_id = 6495407; 
 
   // Book 2 specification 
   strcpy( Book2.title, "Telecom Billing"); 
   strcpy( Book2.author, "Yakit Singha"); 
   strcpy( Book2.subject, "Telecom"); 
   Book2.book_id = 6495700; 
  
   // Print Book1 info, passing address of structure 
   printBook( &Book1 ); 
 
   // Print Book1 info, passing address of structure 
   printBook( &Book2 ); 
 
   return 0; 
} 
// This function accept pointer to structure as parameter. 
void printBook( struct Books *book ) 
{ 
   cout << "Book title : " << book->title <<endl; 
   cout << "Book author : " << book->author <<endl; 
   cout << "Book subject : " << book->subject <<endl; 
   cout << "Book id : " << book->book_id <<endl; 
} 
When the above code is compiled and executed, it produces the following result: 
Book title : Learn C++ Programming 
Book author : Chand Miyan 
Book subject : C++ Programming 
Book id : 6495407 
Book title : Telecom Billing 
Book author : Yakit Singha 
Book subject : Telecom 
Book id : 6495700