Task_Tracker.java

import java.util.ArrayList;
import java.util.Scanner;

class Task {
    private String description;
    private boolean completed;

    public Task(String description) {
        this.description = description;
        this.completed = false;
    }

    public String getDescription() {
        return description;
    }

    public boolean isCompleted() {
        return completed;
    }

    public void markCompleted() {
        completed = true;
    }
}

class TaskTracker {
    private ArrayList<Task> tasks;

    public TaskTracker() {
        tasks = new ArrayList<>();
    }

    public void addTask(String description) {
        Task newTask = new Task(description);
        tasks.add(newTask);
        System.out.println("Task added: " + description);
    }

    public void markTaskCompleted(int index) {
        if (index >= 0 && index < tasks.size()) {
            Task task = tasks.get(index);
            task.markCompleted();
            System.out.println("Task marked as completed: " + task.getDescription());
        } else {
            System.out.println("Invalid task index.");
        }
    }

    public void displayTasks() {
        System.out.println("Task List:");
        for (int i = 0; i < tasks.size(); i++) {
            Task task = tasks.get(i);
            System.out.println((i + 1) + ". " + task.getDescription() +
                    (task.isCompleted() ? " - Completed" : ""));
        }
    }
}

public class TaskTrackerApp {
    public static void main(String[] args) {
        TaskTracker taskTracker = new TaskTracker();
        Scanner scanner = new Scanner(System.in);

        while (true) {
            System.out.println("\n1. Add Task\n2. Mark Task as Completed\n3. Display Tasks\n4. Exit");
            System.out.print("Choose an option: ");

            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume the newline character

            switch (choice) {
                case 1:
                    System.out.print("Enter task description: ");
                    String description = scanner.nextLine();
                    taskTracker.addTask(description);
                    break;

                case 2:
                    System.out.print("Enter the index of the task to mark as completed: ");
                    int index = scanner.nextInt();
                    taskTracker.markTaskCompleted(index - 1); // Adjust index for user input
                    break;

                case 3:
                    taskTracker.displayTasks();
                    break;

                case 4:
                    System.out.println("Exiting the Task Tracker. Goodbye!");
                    System.exit(0);

                default:
                    System.out.println("Invalid choice. Please choose a valid option.");
            }
        }
    }
}