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

Matthew Musni
Matthew Musni
610 Points
Posted by Matthew Musni
Matthew Musni
610 Points

I don't much get how to properly execute the catch Format exception

my program seems to respond when there's an invalid input but i dont know how to start over back to top to reset and ask input from the user

Program.cs 
using System;

namespace Treehouse.CodeChallenges
{
    class Program
    {
        static void Main()
        {
            Console.Write("Enter the number of times to print \"Yay!\": ");
            int number = 0;

            string input = Console.ReadLine();



                while (true)
                {
                try
                {
                    var final = int.Parse(input);
                    Console.WriteLine("Yay!");
                    number += 1;


                    if (final == number)
                    {
                        Console.ReadKey();
                        break;
                    }
                }


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

                }
                continue;
                }



        }
    }
}
Jon Wood
Jon Wood
9,884 Points
Jon Wood
Jon Wood
9,884 Points

It looks like it does repeat when I input something invalid. Did you want it to ask for input again after it does that?

Matthew Musni
Matthew Musni
610 Points
Matthew Musni
Matthew Musni
610 Points

yeah i want to ask for input again

Bernadette Isaacson
Bernadette Isaacson
13,736 Points
Bernadette Isaacson
Bernadette Isaacson
13,736 Points

One way to do it, would be to use TryParse:

static void Main(string[] args)
{
            Console.Write("Enter the number of times to print \"Yay!\": ");
            string result = Console.ReadLine();

            int x;
            while (!int.TryParse(result, out x))
            {
                Console.WriteLine("You must enter a whole number.");
                Console.Write("Enter the number of times to print \"Yay!\": ");
                result = Console.ReadLine();
            }

            for (int i = 1; i <= x; i++)
            {
                Console.WriteLine("Yay!");
            }
}
Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

While tryParse can be used for validity testing in your own code, this challenge specifically requires try and catch.

You do not want to ask for input again, that will fail the challenge.

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

I see a few issues here:

  • if the input is bad, the loop in the current code runs forever
  • you might want to test the number just once, before the loop
  • you don't want to call ReadKey inside (or after) the loop, it would keep the program from ending
  • an explicit continue is unnecessary at the end of a loop