Description

You can check your solutions here: https://judge.softuni.bg/Contests/1489/Iterators-and-Comparators-Lab
1. Library
NOTE: You need the namespace IteratorsAndComparators.
Create a class Book, which should have three public properties:
• string Title
• int Year
• List<string> Authors
Authors can be anonymous, one or many. A Book should have only one constructor.
Create a class Library, which should store a collection of books and implement the IEnumerable<Book> interface.
• List<Book> books
A Library could be intilized without books or with any number of books and should have only one constructor.
Examples
StartUp.cs
public static void Main()
{
Book bookOne = new Book(“Animal Farm”, 2003, “George Orwell”);
Book bookTwo = new Book(“The Documents in the Case”, 2002, “Dorothy Sayers”, “Robert Eustace”);
Book bookThree = new Book(“The Documents in the Case”, 1930);
Library libraryOne = new Library();
Library libraryTwo = new Library(bookOne, bookTwo, bookThree); }

Solution

2. Library Iterator
NOTE: You need the namespace IteratorsAndComparators.
Extend your solution from the prevoius task. Inside the Library class create a nested class LibraryIterator, which should implement the IEnumerator<Book> interface. Try to implement the bodies of the inherited methods by yourself. You will need two more members:
• List<Book> books
• int currentIndex
Now you should be able to iterate through a Library in the Main method.
Examples
Startup.cs
public static void Main()
{
Book bookOne = new Book(“Animal Farm”, 2003, “George Orwell”);
Book bookTwo = new Book(“The Documents in the Case”, 2002, “Dorothy Sayers”, “Robert Eustace”);
Book bookThree = new Book(“The Documents in the Case”, 1930);
Library libraryOne = new Library();
Library libraryTwo = new Library(bookOne, bookTwo, bookThree);

foreach (var book in libraryTwo)
{
Console.WriteLine(book.Title); }
}

Output
Animal Farm
The Documents in the Case
The Documents in the Case

Solution

3. Comparable Book
NOTE: You need the namespace IteratorsAndComparators.
Extend your solution from the prevoius task. Implement the IComparable<Book> interface in the existing class Book. The comparison between two books should happen in the following order:
• First sort them in ascending chronological order (by year)
• If two books are published in the same year, sort them alphabetically
Override the ToString() method in your Book class, so it returns a string in the format:
• “{title} – {year}”
Change your Library class, so that it stores the books in the correct order.
Examples
Startup.cs
public static void Main()
{
Book bookOne = new Book(“Animal Farm”, 2003, “George Orwell”);
Book bookTwo = new Book(“The Documents in the Case”, 2002, “Dorothy Sayers”, “Robert Eustace”);
Book bookThree = new Book(“The Documents in the Case”, 1930);
Library libraryOne = new Library();
Library libraryTwo = new Library(bookOne, bookTwo, bookThree);

foreach (var book in libraryTwo) {
Console.WriteLine(book);
}
}
Examples
Output
The Documents in the Case – 1930
The Documents in the Case – 2002
Animal Farm – 2003

Solution

4. Book Comparator
NOTE: You need the namespace IteratorsAndComparators.
Extend your solution from the prevoius task. Create a class BookComparator, which should implement the IComparer<Book> interface and thus include the following method:
• int Compare(Book, Book)
BookComparator must compare two books by:
1. Book title – alphabetical order
2. Year of publishing a book – from the newest to the oldest
Modify your Library class once again to implement the new sorting.
Examples
Startup.cs
public static void Main()
{
Book bookOne = new Book(“Animal Farm”, 2003, “George Orwell”);
Book bookTwo = new Book(“The Documents in the Case”, 2002, “Dorothy Sayers”, “Robert Eustace”);
Book bookThree = new Book(“The Documents in the Case”, 1930);
Library library = new Library(bookOne, bookTwo, bookThree); }

Output
Animal Farm – 2003
The Documents in the Case – 2002
The Documents in the Case – 1930

Solution