Use the while and do-while to manage the program flow

Program.cs

namespace implement_program_flow
{
    class Program
    {
        static void Main(string[] args)
        {
            var mainstreamCount = 0;

            while (mainstreamCount > 0)
            {
                Console.WriteLine($"MainstreamCount: {mainstreamCount}");
                mainstreamCount--;
            }

            do
            {
                Console.WriteLine("At least this executes once!");
                mainstreamCount--;
            } while (mainstreamCount > 0);

        }
    }
}