We're going to create a program which will allow the user to add values to a list, print the values, and print the sum of all the values. Part of this program will be a simple user interface. 1. In the Program class, add a static list of doubles: private static List _values = new List(); this is the list of doubles we'll be working with in the program. 2. Add readInteger (string prompt), and ReadDouble(string prompt) to the Program class. These should be identical to those in above code. 3. Add a public enum named UserOption . Give it the values/options of: NewValue, Sum, print and Quit. This enumeration will be used later on in the program to create the user interface menu. public enum UserOption { // values } 4. One of the actions our user will be able to take is to add a new value into the list. Let's create the method that will do this. Here is something to get you started: public static void AddValueToList() { // code goes here } Remember, we can use the Add() method on the List class to add items to a list, and we can use the readDouble () method to get a value from the user. 5. The second action our program can perform is printing values to the screen. To do this, create another iterate over public static void method named Print (). In Print(), use a foreach loop to iterate over values, printing each value to the console. 6. Finally, we need to be able to sum the values. This is yet another method public static void method, which should do the following: Create a local double variable called sum and initialise it to 0. Use a foreach loop to iterate over each element in values . Each iteration, add the value in each element to the sum. Write sum to the console. 7. Now that we have the functionality of our list implemented in our code, let's add the code which will allow the user to interact with the program! Let's take a look at the ReadUserOption() method: public static UserOption ReadUserOption() { Console.WriteLine("Enter 0 to add a value"); Console.WriteLine("Enter 1 to add a sum all values"); Console.WriteLine("Enter 2 to print a sum all values"); Console.WriteLine("Enter 3 to quit"); int option = 3; Int32.TryParse(Console.ReadLine(), out option); return (UserOption)option; } You can see it simply presents the possible options to the user, and then reads the option from the user. Note that by default, the method will return (exit). Create the time it should Main () method. The Main method should loop until the user opts to quit, each time it should switch (ReadUserOption()) and use the returned UserOption value to call the appropriate method. Create a screenshot of your program running, and upload it to OnTrack along with the code files for this task.!