Unlimited Sum - C# Programming Exercise

// Importing necessary namespaces for basic functionality
using System;
using System.Collections.Generic; // For using List

class Program
{
    static void Main(string[] args)
    {
        // List to store the numbers entered by the user
        List numbers = new List();

        // Start an infinite loop to keep asking the user for input
        while (true)
        {
            // Prompt user to enter a number or command
            Console.Write("Number or command? ");
            string input = Console.ReadLine();

            // Check if the input is a command
            if (input == "sum")
            {
                // Calculate the sum of all entered numbers
                int sum = 0;
                foreach (int number in numbers)
                {
                    sum += number;
                }
                // Display the sum
                Console.WriteLine("Sum = " + sum);
            }
            else if (input == "view")
            {
                // Display all the numbers entered so far
                Console.WriteLine("Entered numbers:");
                foreach (int number in numbers)
                {
                    Console.WriteLine(number);
                }
            }
            else if (input == "end")
            {
                // Exit the program
                break;
            }
            else
            {
                // Try to convert the input to a number
                if (int.TryParse(input, out int number))
                {
                    // Add the number to the list if it is valid
                    numbers.Add(number);
                }
                else
                {
                    // Inform the user if the input is invalid
                    Console.WriteLine("Invalid input, please enter a number or a valid command.");
                }
            }
        }

        Console.WriteLine("Program has ended.");
    }
}