using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using static System.Console;
namespace Entity2
{
    class Student_
    {
        public Student_() { }
        public string Name { get; set; }
        public int roll_No { get; set; }
        public int Class { get; set; }
        public void Get_Student_Info(Address Obj)
        {
            WriteLine($"Student Name={this.Name}\n Roll_No={this.roll_No}\n Class={this.Class}\n");
            Obj.Get_Address();
        }
    }
    class Address
    {
        public Address() { }
        public string Street { get; set; }
        public string City { get; set; }
        public string State { get; set; }
        public string Pincode { get; set; }
        public void Get_Address()
        {
            WriteLine($"Street={this.Street} \n City={this.City} \n State={this.State}\n Pincode={this.Pincode}");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Student_ Stu_Obj = new Student_();
            Stu_Obj.Name = "Pankaj Choudhary";
            Stu_Obj.roll_No = 1210038;
            Stu_Obj.Class = 12;

            Address Obj = new Address();
	            Obj.City = "Alwar";
            Obj.Street = "P-20 Gandhi Nagar";
            Obj.State = "Rajasthan";
            Obj.Pincode = "301001";

            Stu_Obj.Get_Student_Info(Obj);
            ReadLine();
        }
    }
}

using System;
using System.Collections.Generic;

namespace LibraryManagementSystem
{
    // Inheritance: Base class Person
    class Person
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }

    // Inheritance: Derived class Librarian (IS-A Person)
    class Librarian : Person
    {
        public void IssueBook(Member member, Book book)
        {
            Console.WriteLine($"{Name} (Librarian) issued '{book.Title}' to {member.Name}.");
        }
    }

    // Inheritance: Derived class Member (IS-A Person)
    class Member : Person
    {
        public LibraryCard Card { get; set; } // Association with LibraryCard
        public Address MemberAddress { get; set; } // Aggregation with Address
    }

    // Composition: Library contains other objects
    class Library
    {
        public string LibraryName { get; set; }
        public List<Bookshelf> Bookshelves { get; set; }
		public Library()
		{
			Bookshelves =  new List<Bookshelf>();
		}

        public void AddBookshelf(Bookshelf shelf)
        {
            Bookshelves.Add(shelf);
        }

        public void DisplayLibraryInfo()
        {
            Console.WriteLine($"Welcome to {LibraryName} Library!");
            Console.WriteLine($"We have {Bookshelves.Count} bookshelves.");
        }
    }

    // Composition: Bookshelf is part of Library
    class Bookshelf
    {
        public int ShelfNumber { get; set; }
        public List<Book> Books { get; set; } = new List<Book>();

        public void AddBook(Book book)
        {
            Books.Add(book);
        }
    }

    // Association: Book can be shared between Members and Library
    class Book
    {
        public string Title { get; set; }
        public string Author { get; set; }
    }

    // Aggregation: Address can exist independently of Member
    class Address
    {
        public string Street { get; set; }
        public string City { get; set; }
        public string State { get; set; }
        public string Pincode { get; set; }
    }

    // Composition: LibraryCard is a part of Member
    class LibraryCard
    {
        public int CardNumber { get; set; }
        public DateTime IssuedDate { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // Create Library
            Library library = new Library { LibraryName = "Central Library" };

            // Create Bookshelf and Books
            Bookshelf shelf1 = new Bookshelf { ShelfNumber = 1 };
            shelf1.AddBook(new Book { Title = "C# Programming", Author = "John Doe" });
            shelf1.AddBook(new Book { Title = "Data Structures", Author = "Jane Smith"});

            // Add Bookshelf to Library (Composition)
            library.AddBookshelf(shelf1);

            // Display Library Info
            library.DisplayLibraryInfo();

            // Create Member with Aggregated Address
            Address memberAddress = new Address
            {
                Street = "123 Main St",
                City = "Metropolis",
                State = "NY",
                Pincode = "10001"
            };

            Member member = new Member
            {
                Name = "Alice",
                Age = 25,
                MemberAddress = memberAddress,
                Card = new LibraryCard { CardNumber = 101, IssuedDate = DateTime.Now }
            };

            // Create Librarian
            Librarian librarian = new Librarian
            {
                Name = "Mr. Smith",
                Age = 40
            };

            // Issue Book (Association)
            Book selectedBook = shelf1.Books[0]; // Select the first book on the shelf
            librarian.IssueBook(member, selectedBook);

            // Display Member Info and Address
            Console.WriteLine($"Member Info:\nName: {member.Name}\nAddress: {member.MemberAddress.Street}, {member.MemberAddress.City}");
        }
    }
}