// Create a basic task manager program that stores and displays up to three tasks using individual string variables. 

// The tasks can be marked as completed using Boolean flags, and the program will display which tasks are completed or still pending.

​

using System;

public class TaskManager

{

    // STEP 1: Create Variables for Tasks and Their Status

    // Set up three string variables to store the tasks.

    // Create three Boolean variables to track whether each task is completed.

    public static string task1 = "";

    public static string task2 = "";

    public static string task3 = "";

    public static bool task1Completed = false;

    public static bool task2Completed = false;

    public static bool task3Completed = false;

    public static void Main()

    {

        // Create a loop that runs until user quits

        Console.WriteLine("Choose option - (1)=Add Task, (2)=Mark Complete, (3)=Display Tasks, (4)=Quit: ");

        string userOption = Console.ReadLine();

​

        while (userOption != "4") 

        {

            if (userOption == "1")

                EnterTask();

            else if (userOption == "2")

                MarkCompleted();

            else if (userOption == "3")

                DisplayTasks();

​

            if (userOption != "4") {

                Console.WriteLine("Choose option - (1)=Add Task, (2)=Mark Complete, (3)=Display Tasks, (4)=Quit: ");

                userOption = Console.ReadLine();        

            }           

    }

    static void EnterTask()

    {

        // STEP 2: Prompt User to Add a Task

        // Ask the user to input a task.

        // Check which task variable is empty and store the new task in that variable.

        // If all task slots are full, inform the user that no more tasks can be added.

        Console.WriteLine("Enter a new task: ");

        string newTask = Console.ReadLine();        

​

            if (string.IsNullOrEmpty(task1))

            {

                task1 = newTask;

            }

            else if (string.IsNullOrEmpty(task2))

            {

                task2 = newTask;

            }

            else if (string.IsNullOrEmpty(task3))

            {

                task3 = newTask;

            }

            else

            {

                Console.WriteLine("Task list is full.");

            }       

        }

    }

    public static void MarkCompleted()

    {

        // STEP 3: Mark a Task as Completed 

        // Ask the user to choose which task (1, 2, or 3) to mark as completed.

        // Use if-else conditions to update the corresponding Boolean variable, marking the task as completed. 

        // Use if-else conditions to update the task status and Send/Display a confirmation message to the user.

        // If the user selects an invalid task number, display an error message.

        Console.WriteLine("Which task would you like to mark as completed (1, 2, or 3)?");

        int taskToComplete = int.Parse(Console.ReadLine());

        if(taskToComplete == 1 && !string.IsNullOrEmpty(task1))

        {

            task1Completed =  true;

            Console.WriteLine("Task 1 marked as completed.");

        }

        else if(taskToComplete == 2 && !string.IsNullOrEmpty(task2))

        {

            task2Completed =  true;

            Console.WriteLine("Task 2 marked as completed.");

        }

        else if(taskToComplete == 3 && !string.IsNullOrEmpty(task3))

        {

            task3Completed =  true;

            Console.WriteLine("Task 3 marked as completed.");

        }   

        else

        {

            Console.WriteLine("Invalid task selection.");

        }

    }

    public static void DisplayTasks()

    {

        // Display the Tasks and Their Status

        // Print out each task along with its status (either "Completed" or "Pending").

        // Use if-else conditions to check whether each task is completed or not and display the appropriate status.

        Console.WriteLine("Your Tasks:");

        if (!string.IsNullOrEmpty(task1)) 

        {

            Console.WriteLine(task1Completed ? "Task 1: " + task1 + " [Completed]" : "Task 1: " + task1 + " [Pending]");

        }

        if (!string.IsNullOrEmpty(task2)) 

        {

            Console.WriteLine(task2Completed ? "Task 2: " + task2 + " [Completed]" : "Task 2: " + task2 + " [Pending]");

        }

        if (!string.IsNullOrEmpty(task3)) 

        {

            Console.WriteLine(task3Completed ? "Task 3: " + task3 + " [Completed]" : "Task 3: " + task3 + " [Pending]");

        }   

​

    }

}