diff --git a/src/main/java/Book.java b/src/main/java/Book.java
index 7cff6f8..6453fec 100644
--- a/src/main/java/Book.java
+++ b/src/main/java/Book.java
@@ -1,3 +1,22 @@
 public class Book {
     //Book should contain name,author,year of publish and ISBN
-}
+    private String bookName;
+    private String author;
+    private int year;
+    private int ISBN;
+
+    public Book(String bookName, String author, int year, int ISBN) {
+        this.bookName = bookName;
+        this.author = author;
+        this.year = year;
+        this.ISBN = ISBN;
+    }
+
+    public String getNameOfBook() {
+        return this.bookName + "";
+    }
+
+    public int getNumberOfBook() {
+        return this.ISBN;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/Librarian.java b/src/main/java/Librarian.java
index 321ce3a..14049ce 100644
--- a/src/main/java/Librarian.java
+++ b/src/main/java/Librarian.java
@@ -1,10 +1,17 @@
 public class Librarian {
-    /*
-    * The librarian should have a username and a password
-    * The librarian should be able to search users, librarians and books
-    * The librarian should be able to add\remove\update user add\remove\update_
-    _ librarian and add\remove\update book
-     */
+    private String username;
+    private String password;
 
+    public Librarian(String username, String password){
+        this.username = username;
+        this.password = password;
+    }
 
+    public String getUsername() {
+        return this.username;
+    }
+
+    public String getPassword() {
+        return this.password;
+    }
 }
diff --git a/src/main/java/Library.java b/src/main/java/Library.java
index 6c34354..7a76a5a 100644
--- a/src/main/java/Library.java
+++ b/src/main/java/Library.java
@@ -1,3 +1,7 @@
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
 public class Library {
     /*
     * The library should have a list of books.
@@ -6,79 +10,200 @@ public class Library {
     * The library should have a list of users and a list of librarians.
      */
 
-    //book related functions
+    private String libraryName;
+    private String book = "Harry Potter";
+    private int num = 2;
+    private String librarian = "firstLibrarian";
+    private String User = "Haleh";
+    private String pass = "0000";
+
+    private static Librarian firstLibrarian = new Librarian("firstLibrarian", "0000");
+    private static Book firstBook = new Book("Harry Potter", "J. K. Rowling", 1997, 2);
+    private static User firstUser = new User("Haleh", "0000");
+
+    //book
+    private ArrayList<String> ExistedBooks;
+    private static Map<String, Integer> NumberOfBooks;
+
+    //librarian  user
+    private static ArrayList<User> Users = new ArrayList<User>();
+    private static ArrayList<Librarian> Librarians = new ArrayList<Librarian>();
+    private static Map<String, String> users = new HashMap<String, String>();
+    private static Map<String, String> librarians;
+
+    public Library(String libraryName) {
+        this.libraryName = libraryName;
+        ExistedBooks = new ArrayList<String>();
+        ExistedBooks.add(book);
+        NumberOfBooks = new HashMap<String, Integer>();
+        NumberOfBooks.put(book, num);
 
-    public void addBook(){
-        //TODO
+        Librarians = new ArrayList<Librarian>();
+        Librarians.add(firstLibrarian);
+        librarians = new HashMap<String, String>();
+        librarians.put(librarian, pass);
+
+        Users = new ArrayList<User>();
+        Users.add(firstUser);
+        users = new HashMap<String, String>();
+        users.put(User, pass);
     }
 
-    public void removeBook(){
-        //TODO
+    public ArrayList<String> getExistedBooks() {
+        return ExistedBooks;
     }
 
-    public void searchBook(){
-        //TODO
+    public Map<String, Integer> getNumberOfBooks() {
+        return NumberOfBooks;
     }
 
-    public void updateBook(){
-        //TODO
+    public ArrayList<Librarian> getLibrarians() {
+        return Librarians;
     }
 
-    public void doesBookExist(){
-        //TODO
+    public Map<String, String> getlibrarians() {
+        return librarians;
     }
 
-    public void increaseBook(){
-        //TODO
+    public ArrayList<User> getUsers() {
+        return Users;
     }
 
-    public void decreaseBook(){
-        //TODO
+    public Map<String, String> getusers() {
+        return users;
     }
 
-    //user related functions
+    ArrayList<String> rentedBooks = firstUser.getRentedBooks();
+
+    //book related functions
 
-    public void addUser(){
-        //TODO
+    public void addBook(Book book){
+        ExistedBooks.add(book.getNameOfBook());
+        NumberOfBooks.put(book.getNameOfBook(), book.getNumberOfBook());
     }
 
-    public void removeUser(){
-        //TODO
+    public void removeBook(String bookName){
+        if(doesBookExist(bookName)) {
+            ExistedBooks.remove(bookName);
+            NumberOfBooks.remove(bookName);
+            System.out.println(bookName + " is removed!");
+        } else {
+            System.out.println("This book doesn't exist!");
+        }
     }
 
-    public void searchUser(){
-        //TODO
+    public boolean doesBookExist(String bookName) {
+        if(NumberOfBooks.containsKey(bookName) && NumberOfBooks.get(bookName) != 0){
+            return true;
+        } else {
+            System.out.println("No book in the list!");
+        }
+        return false;
     }
 
-    public void updateUser(){
-        //TODO
+    public void searchBook(String bookName){
+        if(doesBookExist(bookName)) {
+            System.out.println("We have " + bookName);
+        } else {
+            System.out.println("No book with name " + bookName);
+        }
     }
 
-    public void doesUserExist(){
-        //TODO
+    public void rentBook(String book){
+        if(doesBookExist(book)){
+            NumberOfBooks.put(book, NumberOfBooks.get(book) - 1);
+            firstUser.rentBook(book);
+        } else {
+            System.out.println("Number of this book = 0");
+        }
     }
 
-    //librarian related functions
+    public void returnBook(String book){
+        NumberOfBooks.put(book, NumberOfBooks.get(book) + 1);
+        firstUser.returnBook(book);
+    }
 
-    public void addLibrarian(){
-        //TODO
+    //user related functions
+
+    public void addUser(User user){
+        Users.add(user);
+        users.put(user.getUsername(), user.getPassword());
+    }
+
+    public void removeUser(User user){
+        if(doesUserExist(user)) {
+            Users.remove(user);
+            users.remove(user.getUsername());
+            System.out.println(user.getUsername() + " is removed!");
+        } else {
+            System.out.println("This book doesn't exist!");
+        }
+    }
+
+    public boolean doesUserExist(User user){
+        if(users.containsKey(user.getUsername()) && users.containsValue(user.getPassword())){
+            return true;
+        } else {
+            System.out.println("No member in the list!");
+        }
+        return false;
     }
 
-    public void removeLibrarian(){
-        //TODO
+    public void searchUser(User user){
+        if(doesUserExist(user)) {
+            System.out.println(user.getUsername() + " exists");
+        } else {
+            System.out.println("No member with username " + user.getUsername());
+        }
     }
 
-    public void searchLibrarian(){
-        //TODO
+    public void loginUser(User user){
+        if(doesUserExist(user)) {
+            System.out.println("Hello " + user.getUsername());
+        } else {
+            System.out.println("No member with username " + user.getUsername());
+        }
     }
 
-    public void updateLibrarian(){
-        //TODO
+    //librarian related functions
+
+    public void addLibrarian(Librarian librarian){
+        Librarians.add(librarian);
+        librarians.put(librarian.getUsername(), librarian.getPassword());
+    }
+
+    public void removeLibrarian(Librarian librarian){
+        if(doesLibrarianExist(librarian)) {
+            Librarians.remove(librarian);
+            librarians.remove(librarian.getUsername());
+            System.out.println(librarian.getUsername() + " is removed!");
+        } else {
+            System.out.println("This librarian doesn't exist!");
+        }
     }
 
-    public void doesLibrarianExist(){
-        //TODO
+    public boolean doesLibrarianExist(Librarian librarian){
+        if(librarians.containsKey(librarian.getUsername()) && librarians.containsValue(librarian.getPassword())){
+            return true;
+        } else {
+            System.out.println("No librarian in the list!");
+        }
+        return false;
     }
 
+    public void searchLibrarian(Librarian librarian){
+        if(doesLibrarianExist(librarian)) {
+            System.out.println(librarian.getUsername() + " exists");
+        } else {
+            System.out.println("No member with username " + librarian.getUsername());
+        }
+    }
 
+    public void loginLibrarian(Librarian librarian){
+        if(doesLibrarianExist(librarian)) {
+            System.out.println("Hello " + librarian.getUsername());
+        } else {
+            System.out.println("No member with username " + librarian.getUsername());
+        }
+    }
 }
diff --git a/src/main/java/Main.java b/src/main/java/Main.java
index 9a347d3..2475fbc 100644
--- a/src/main/java/Main.java
+++ b/src/main/java/Main.java
@@ -1,18 +1,161 @@
 import java.util.Scanner;
+import java.util.ArrayList;
+import java.util.Map;
 
 public class Main {
     /*
-    * make a functional library app using oop
-    * run the main program in Main.java and code the oop part in other classes
-    * don't forget to add at least 1 librarian to the library to make it functionable.
-    * *  *** don't limit yourself to our template ***
+     * make a functional library app using oop
+     * run the main program in Main.java and code the oop part in other classes
+     * don't forget to add at least 1 librarian to the library to make it functionable.
+     * *  *** don't limit yourself to our template ***
      */
 
-    public static void main(String[] args) {
+    private static Scanner sc = new Scanner(System.in);
+    private static Library library = new Library("sun");
+    //librarian
+    private static Librarian firstLibrarian = new Librarian("firstLibrarian", "0000");
+    private static Book firstBook = new Book("Harry Potter", "J. K. Rowling", 1997, 2);
+    private static User firstUser = new User("Haleh", "0000");
 
+    ArrayList<String> ExistedBooks = library.getExistedBooks();
+    Map<String, Integer> NumberOfBooks = library.getNumberOfBooks();
+    ArrayList<Librarian> Librarians = library.getLibrarians();
+    Map<String, String> librarians = library.getlibrarians();
+    ArrayList<User> Users = library.getUsers();
+    Map<String, String> users = library.getusers();
+
+    public static void main(String[] args){
+        do
+        {       System.out.println("Enter your choice from the following menu:");
+                System.out.println("1.User 2.Librarian 3.Exit");
+                int choice;
+                choice = sc.nextInt();
+            if(choice == 1){
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    User newUser = new User(username, password);
+                    if(library.doesUserExist(newUser)){
+                        library.loginUser(newUser);
+                    } else {
+                        break;
+                    }
+            }
+            else if(choice == 2){
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    Librarian newLibrarian = new Librarian(username, password);
+                    if(library.doesLibrarianExist(newLibrarian)){
+                        library.loginLibrarian(newLibrarian);
+                    } else {
+                        break;
+                    }
+            }
+                else {
+                    break;
+                }
+                runMenu(choice);
+        }while(true);
     }
 
-    public static void runMenu(){
-        //TODO:
+
+    public static void runMenu(int choice) {
+        int ex = 0;
+        do {
+            int option;
+            if (choice == 1) {
+                System.out.println("Enter your choice from the following menu:");
+                System.out.println("1.Rent Book 2.Return Book 3.Exit");
+                option = sc.nextInt();
+                if (option == 1) {
+                    System.out.println("Book name: ");
+                    String bookName = sc.next();
+                    library.rentBook(bookName);
+                } else if (option == 2) {
+                    System.out.println("Book name: ");
+                    String bookName = sc.next();
+                    library.returnBook(bookName);
+                } else {
+                    break;
+                }
+                System.out.println("Do you want to continue? 1.Yes 2.No");
+                ex = sc.nextInt();
+            } else if (choice == 2) {
+                System.out.println("Enter your choice from the following menu:");
+                System.out.println("1.Add Book 2.Remove Book 3.Search Book");
+                System.out.println("4.Add User 5.Remove User 6.Search User");
+                System.out.println("7.Add Librarian 8.Remove librarian 9.Search Librarian");
+                option = sc.nextInt();
+                if (option == 1) {
+                    System.out.println("Book name: ");
+                    String bookName = sc.next();
+                    System.out.println("Author name: ");
+                    String authorName = sc.next();
+                    System.out.println("Year of publish: ");
+                    int Year = sc.nextInt();
+                    System.out.println("ISBN: ");
+                    int ISBN = sc.nextInt();
+                    Book newBook = new Book(bookName, authorName, Year, ISBN);
+                    library.addBook(newBook);
+                } else if (option == 2) {
+                    System.out.println("Book name: ");
+                    String bookName = sc.next();
+                    library.removeBook(bookName);
+                } else if (option == 3) {
+                    System.out.println("Book name: ");
+                    String bookName = sc.next();
+                    library.searchBook(bookName);
+                } else if (option == 4) {
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    User newUser = new User(username, password);
+                    library.addUser(newUser);
+                } else if (option == 5) {
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    User newUser = new User(username, password);
+                    library.removeUser(newUser);
+                } else if (option == 6) {
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    User newUser = new User(username, password);
+                    library.searchUser(newUser);
+                } else if (option == 7) {
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    Librarian newLibrarian = new Librarian(username, password);
+                    library.addLibrarian(newLibrarian);
+                } else if (option == 8) {
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    Librarian newLibrarian = new Librarian(username, password);
+                    library.removeLibrarian(newLibrarian);
+                } else if (option == 9) {
+                    System.out.println("Username: ");
+                    String username = sc.next();
+                    System.out.println("Password: ");
+                    String password = sc.next();
+                    Librarian newLibrarian = new Librarian(username, password);
+                    library.searchLibrarian(newLibrarian);
+                } else {
+                    break;
+                }
+                System.out.println("Do you want to continue? 1.Yes 2.No");
+                ex = sc.nextInt();
+            }
+        } while (ex == 1);
     }
 }
diff --git a/src/main/java/User.java b/src/main/java/User.java
index dbe4020..493e2c9 100644
--- a/src/main/java/User.java
+++ b/src/main/java/User.java
@@ -1,12 +1,40 @@
-public class User {
+import java.util.ArrayList;
+
+public class User<username> {
     //User should have a list of books
     //User should have a username and a password
 
-    public void rentBook(){
-        //TODO
+    String book = "0";
+    ArrayList<String> rentedBooks;
+    private String username;
+    private String password;
+
+    public User(String username, String password){
+        this.username = username;
+        this.password = password;
+        rentedBooks = new ArrayList<String>();
+        rentedBooks.add(book);
+    }
+
+    public ArrayList<String> getRentedBooks() {
+        return rentedBooks;
+    }
+
+    public String getUsername() {
+        return this.username;
+    }
+
+    public String getPassword() {
+        return this.password;
+    }
+
+    public void rentBook(String book){
+        rentedBooks.add(book);
+        System.out.println("You've rented " + book);
     }
 
-    public void returnBook(){
-        //TODO
+    public void returnBook(String book){
+        rentedBooks.remove(book);
+        System.out.println("You've returned " + book);
     }
-}
+}
\ No newline at end of file