C# STRUCTURES

In C#, a structure is a value type data type. It helps you to make a single variable hold related data of various data types. The struct keyword is used for creating a structure.

To define a structure, you must use the struct statement. The struct statement defines a new data type, with more than one member for your program.

using System;

namespace ConsoleApp1
{
    struct Books
    {
        public string title;
        public string author;
 public string subject;
        public int book_id;
    };
    public class testStructure
    {
        public 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 Ali";
            Book1.subject = "C Programming Tutorial";
            Book1.book_id = 6495407;
            /* book 2 specification */
            Book2.title = "Telecom Billing";
            Book2.author = "Zara Ali";
            Book2.subject = "Telecom Billing 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();

            //Book 1 title: C Programming
            //Book 1 author: Nuha Ali
            //Book 1 subject: C Programming Tutorial
            //Book 1 book_id: 6495407
            //Book 2 title: Telecom Billing
            //Book 2 author: Zara Ali
            //Book 2 subject: Telecom Billing Tutorial
            //Book 2 book_id: 6495700
        }
    }
}

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 connot be changed.
• Unlike 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. Unlike 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 initialized

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

using System;

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

namespace ConsoleApp1
{
    public class testStructure
    {
        public 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 Ali", "C Programming Tutorial", 6495407);
            /* book 2 specification */
            Book2.getValues("Telecom Billing",
            "Zara Ali", "Telecom Billing Tutorial", 6495700);
            /* print Book1 info */
            Book1.display();
            /* print Book2 info */
            Book2.display();
            Console.ReadKey();
            //Title: C Programming
            //Author: Nuha Ali
            //Subject: C Programming Tutorial
            //Book_id : 6495407
            //Title: Telecom Billing
            //Author: Zara Ali
            //Subject: Telecom Billing Tutorial
            //Book_id : 6495700
        }
    }
}