Write an application named EnterUppercaseLetters that asks the user to type an uppercase letter from the keyboard. If the character entered is an uppercase letter, display OK; if it is not an uppercase letter, display an error message

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using static System.Console;

namespace EnterUppercaseLetters
{
    class EnterUppercaseLetters
    {
        static void Main(string[] args)
        {
            WriteLine("EnterUppercaseLetters");
            char entry = '0';
            while (entry != '!')
            {
                Write("Enter uppercase letter:");
                entry = char.Parse(ReadLine());
                if (entry >= 'A' && entry <= 'Z')
                    WriteLine("*OK*");
                else
                    WriteLine("Thats not an uppercase letter");
            }

            WriteLine("--End--");
        }
    }
}