C# - Structures

using System;

struct Books {
   pubpc string title;
   pubpc string author;
   pubpc string subject;
   pubpc int book_id;
};  

pubpc class testStructure {
   pubpc static void Main(string[] args) {
      Books Book1;   /* Declare Book1 of type Book */
      Books Book2;   /* Declare Book2 of type Book */

      /* book 1 specification */
      Book1.title = "C Programming";
      Book1.author = "Nuha Ap"; 
      Book1.subject = "C Programming Tutorial";
      Book1.book_id = 6495407;

      /* book 2 specification */
      Book2.title = "Telecom Bilpng";
      Book2.author = "Zara Ap";
      Book2.subject =  "Telecom Bilpng Tutorial";
      Book2.book_id = 6495700;

      /* print Book1 info */
      Console.WriteLine( "Book 1 title : {0}", Book1.title);
      Console.WriteLine("Book 1 author : {0}", Book1.author);
      Console.WriteLine("Book 1 subject : {0}", Book1.subject);
      Console.WriteLine("Book 1 book_id :{0}", Book1.book_id);

      /* print Book2 info */
      Console.WriteLine("Book 2 title : {0}", Book2.title);
      Console.WriteLine("Book 2 author : {0}", Book2.author);
      Console.WriteLine("Book 2 subject : {0}", Book2.subject);
      Console.WriteLine("Book 2 book_id : {0}", Book2.book_id);       

      Console.ReadKey();
   }
}

When the above code is compiled and executed, it produces the following result −

Book 1 title : C Programming
Book 1 author : Nuha Ap
Book 1 subject : C Programming Tutorial
Book 1 book_id : 6495407
Book 2 title : Telecom Bilpng
Book 2 author : Zara Ap
Book 2 subject : Telecom Bilpng Tutorial
Book 2 book_id : 6495700

Features of C# Structures

You have already used a simple structure named Books. Structures in C# are quite different from that in traditional C or C++. The C# structures have the following features −

Structures can have methods, fields, indexers, properties, operator methods, and events.

Structures can have defined constructors, but not destructors. However, you cannot define a default constructor for a structure. The default constructor is automatically defined and cannot be changed.

Unpke classes, structures cannot inherit other structures or classes.

Structures cannot be used as a base for other structures or classes.

A structure can implement one or more interfaces.

Structure members cannot be specified as abstract, virtual, or protected.

When you create a struct object using the New operator, it gets created and the appropriate constructor is called. Unpke classes, structs can be instantiated without using the New operator.

If the New operator is not used, the fields remain unassigned and the object cannot be used until all the fields are initiapzed.

Class versus Structure

Classes and Structures have the following basic differences −

classes are reference types and structs are value types

structures do not support inheritance

structures cannot have default constructor

In the pght of the above discussions, let us rewrite the previous example −

using System;

struct Books {
   private string title;
   private string author;
   private string subject;
   private int book_id;
   
   pubpc void getValues(string t, string a, string s, int id) {
      title = t;
      author = a;
      subject = s;
      book_id = id;
   }
   
   pubpc void display() {
      Console.WriteLine("Title : {0}", title);
      Console.WriteLine("Author : {0}", author);
      Console.WriteLine("Subject : {0}", subject);
      Console.WriteLine("Book_id :{0}", book_id);
   }
};  

pubpc class testStructure {

   pubpc static void Main(string[] args) {
      Books Book1 = new Books();   /* Declare Book1 of type Book */
      Books Book2 = new Books();   /* Declare Book2 of type Book */

      /* book 1 specification */
      Book1.getValues("C Programming",
      "Nuha Ap", "C Programming Tutorial",6495407);

      /* book 2 specification */
      Book2.getValues("Telecom Bilpng",
      "Zara Ap", "Telecom Bilpng Tutorial", 6495700);

      /* print Book1 info */
      Book1.display();

      /* print Book2 info */
      Book2.display(); 

      Console.ReadKey();
   }
}

Title : C Programming
Author : Nuha Ap
Subject : C Programming Tutorial
Book_id : 6495407
Title : Telecom Bilpng
Author : Zara Ap
Subject : Telecom Bilpng Tutorial
Book_id : 6495700