// This text is designed to help you practice touch typing common C# syntax // within the context of a simple console application. using System; using System.Collections.Generic; using System.Linq; // Used for LINQ methods like .Any() and .Where() // 1. Define a Task class to represent individual tasks public class Task { // Auto-implemented properties for task details public int Id { get; } // Unique identifier for the task public string Description { get; set; } // What the task is about public bool IsCompleted { get; private set; } // Status of the task public DateTime DueDate { get; set; } // When the task is due // Static counter to generate unique IDs for new tasks private static int _nextId = 1; // Constructor to initialize a new Task object public Task(string description, DateTime dueDate) { Id = _nextId++; // Assign current ID and then increment for the next task Description = description; IsCompleted = false; // New tasks are not completed by default DueDate = dueDate; } // Method to mark a task as completed public void MarkAsCompleted() { IsCompleted = true; Console.WriteLine($"Task '{Description}' (ID: {Id}) marked as completed."); } // Method to display task information public override string ToString() { // Format the output string for better readability string status = IsCompleted ? "[COMPLETED]" : "[PENDING]"; return $"ID: {Id}, Description: {Description}, Due: {DueDate.ToShortDateString()}, Status: {status}"; } } // 2. Define a TaskManager class to handle task operations public class TaskManager { // A list to store all the tasks private List<Task> _tasks; // Constructor to initialize the TaskManager public TaskManager() { _tasks = new List<Task>(); } // Method to add a new task to the manager public void AddTask(string description, DateTime dueDate) { Task newTask = new Task(description, dueDate); _tasks.Add(newTask); Console.WriteLine($"Added new task: '{description}' (ID: {newTask.Id})"); } // Method to view all tasks, optionally filtering by completion status public void ViewTasks(bool showCompleted = true) { Console.WriteLine("\n--- Your Tasks ---"); if (!_tasks.Any()) // Check if there are any tasks using LINQ { Console.WriteLine("No tasks available."); return; } // Filter tasks based on showCompleted flag var tasksToDisplay = showCompleted ? _tasks : _tasks.Where(t => !t.IsCompleted); foreach (var task in tasksToDisplay) { Console.WriteLine(task.ToString()); } Console.WriteLine("------------------\n"); } // Method to complete a task by its ID public void CompleteTask(int taskId) { // Find the task using LINQ's FirstOrDefault Task taskToComplete = _tasks.FirstOrDefault(t => t.Id == taskId); if (taskToComplete != null) // Check if the task was found { if (!taskToComplete.IsCompleted) { taskToComplete.MarkAsCompleted(); } else { Console.WriteLine($"Task ID {taskId} is already completed."); } } else { Console.WriteLine($"Error: Task with ID {taskId} not found."); } } // Method to remove a task by its ID public void RemoveTask(int taskId) { // Find the task to remove Task taskToRemove = _tasks.FirstOrDefault(t => t.Id == taskId); if (taskToRemove != null) { _tasks.Remove(taskToRemove); // Remove the task from the list Console.WriteLine($"Task '{taskToRemove.Description}' (ID: {taskId}) has been removed."); } else { Console.WriteLine($"Error: Task with ID {taskId} not found for removal."); } } } // 3. Main program entry point public class Program { public static void Main(string[] args) { Console.WriteLine("Welcome to the C# Task Manager!"); TaskManager manager = new TaskManager(); // Create an instance of the TaskManager // Adding some initial tasks for demonstration manager.AddTask("Learn C# basics", DateTime.Now.AddDays(7)); manager.AddTask("Build a console app", DateTime.Now.AddDays(14)); manager.AddTask("Refactor old code", DateTime.Now.AddDays(21)); manager.AddTask("Write unit tests", DateTime.Now.AddDays(30)); // Display all current tasks manager.ViewTasks(); // Simulate completing a task manager.CompleteTask(1); // Mark "Learn C# basics" as completed // Display tasks again, showing the updated status manager.ViewTasks(); // Try to complete an already completed task manager.CompleteTask(1); // Display only pending tasks Console.WriteLine("\n--- Pending Tasks Only ---"); manager.ViewTasks(showCompleted: false); // Simulate removing a task manager.RemoveTask(3); // Remove "Refactor old code" // Display tasks after removal manager.ViewTasks(); // Try to remove a non-existent task manager.RemoveTask(99); Console.WriteLine("\nTask Manager demonstration complete. Keep practicing your C# typing!"); } }