Two .cs files needed for a quiz. the images for the 2 questions are attached.

using System;
namespace Quiz4SquareRootError
{
public class NegativeNumber : Exception
{
public NegativeNumber(string message) : base(message)
{
}
}
class Program
{
static void Main(string[] args)
{
try
{
Console.WriteLine("Please enter a number: ");
string userInput =...