An example of using user defined exceptions

UserDefinedException.cs

void Main()
{
	Console.WriteLine("Do you want to continue? Enter Y for Yes or N for No");
	var answer = Console.ReadLine();
	if (answer.ToUpper() != "Y" && answer.ToUpper() != "N")
	{
		throw new InvalidAnswerException();
	}
}

public class InvalidAnswerException:Exception
{
	public InvalidAnswerException(){}
	public InvalidAnswerException(string message):base(message){}
	public InvalidAnswerException(string message, Exception inner):base(message, inner){}
}