Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

C# C# Basics (Retired) Perfect Final

Jonathan Loescher
PLUS
Jonathan Loescher
Courses Plus Student 1,389 Points
Posted by Jonathan Loescher
Jonathan Loescher
Courses Plus Student 1,389 Points

I have created this program on my computer using visual studio 2015, I receive no errors and the code is exact

On my computer this code works and I receive the correct output. However when running the code on the website I receive the following error, it appears there is no value being assigned to entry.

System.ArgumentNullException: Value cannot be null. Parameter name: String. See output for stack trace.

Program.cs 
using System;

namespace Treehouse.CodeChallenges
{
    class Program
    {
        static void Main()
        {
            while (true) // Repeat until user quits
            {
                Console.Write("Enter the number of times to print \"Yay!\": ");
                var entry = Console.ReadLine();
                try
                {
                    var times = int.Parse(entry);

                    for (int i = 1; i <= times; i++)
                    {
                        Console.WriteLine("Yay!");
                    }

                    break;
                }
                catch (FormatException)
                {
                    Console.WriteLine("You must enter a whole number.");
                    continue;
                }
            }
        }
    }
}

1 Answer

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

:point_right: Your program "works", but deviates from the instructions.

This is a great example of how something that works (will compile an run) might not be what was asked for (satisfies the requirements). This has been a topic of many previous questions (such as this one just earlier today), but I'll repost the info here:

People often over-think this one and get too creative, and their answer is rejected for a variety of reasons (some which don't seem to make any sense).

Here are the secret "rules" you must follow for success on this one:

  • Your program must ask for and accept input ONE TIME ONLY
  • If the input validates, your program will perform exactly as in Task 1
  • If the input does not validate, it will print the error message and exit
  • Validation must be done by exception catching. There are other perfectly good methods that can be used for validation, but they will not pass this challenge

It looks like you have an extra loop that violates items 1 and 3.