LibrarySystem.java

import java.util.*;

class Book {
    int id;
    String title;
    String author;

    Book(int id, String title, String author) {
        this.id = id;
        this.title = title;
        this.author = author;
    }

    public String toString() {
        return "ID: " + id + ", Title: " + title + ", Author: " + author;
    }
}

public class LibrarySystem {
    static List<Book> library = new ArrayList<>();
    static Scanner sc = new Scanner(System.in);

    public static void addBook() {
        System.out.print("Enter Book ID: ");
        int id = sc.nextInt();
        sc.nextLine(); // consume newline
        System.out.print("Enter Title: ");
        String title = sc.nextLine();
        System.out.print("Enter Author: ");
        String author = sc.nextLine();

        library.add(new Book(id, title, author));
        System.out.println("Book added successfully!");
    }

    public static void viewBooks() {
        if (library.isEmpty()) {
            System.out.println("Library is empty.");
            return;
        }
        System.out.println("\n--- Book List ---");
        for (Book b : library) {
            System.out.println(b);
        }
    }

    public static void searchBook() {
        System.out.print("Enter title to search: ");
        sc.nextLine(); // consume newline
        String keyword = sc.nextLine().toLowerCase();
        boolean found = false;

        for (Book b : library) {
            if (b.title.toLowerCase().contains(keyword)) {
                System.out.println("Found: " + b);
                found = true;
            }
        }

        if (!found) System.out.println("No book found with that title.");
    }

    public static void removeBook() {
        System.out.print("Enter Book ID to remove: ");
        int id = sc.nextInt();
        boolean removed = library.removeIf(b -> b.id == id);

        if (removed)
            System.out.println("Book removed successfully.");
        else
            System.out.println("Book not found.");
    }

    public static void main(String[] args) {
        int choice;
        do {
            System.out.println("\n---Library Menu--");
            System.out.println("1. Add Book\n2. View Books\n3. Search Book by Title\n4. Remove Book by ID\n5. Exit");
            System.out.print("Enter your choice: ");
            choice = sc.nextInt();

            switch (choice) {
                case 1: addBook(); break;
                case 2: viewBooks(); break;
                case 3: searchBook(); break;
                case 4: removeBook(); break;
                case 5: System.out.println("Exiting..."); break;
                default: System.out.println("Invalid choice.");
            }
        } while (choice != 5);
    }
}