C# DataBases Lesson 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace Databases
{
    class Program
    {
        static void Main(string[] args)
        {
            //Initial variables
            bool flag = true;
            string name;

            //Reading from the file and putting into list seperated by '\n' so everyline
            string filename = @"testdoc.txt";
            string text = Readfile(filename);
            List<string> Nameslist = new List<string>();
            Nameslist = text.Split('\n').ToList();

            //Resets the file
            WriteFile(filename, "");

            //Keeps the loop running until flag != true
            while (flag)
            {
                //'Q' is halt condition
                Console.WriteLine("Enter the entity or enter 'Q' to quit");
                name = Console.ReadLine();
                if (name == "Q")
                {
                    //End decision
                    Nameslist.Sort();
                    for (int i = 0;i<Nameslist.Count();i++)
                    {
                        AppendFile(filename, Nameslist[i]);
                    }
                    flag = false;
                } else
                {
                    //Add to list devision
                    Nameslist.Add(name);
                }

            }

        }

        static void AppendFile(string filename , string Text)
        {
            StreamWriter File = new StreamWriter(filename, true);
            File.WriteLine("\n"+Text);
            File.Close();
        }
        static void WriteFile(string filename, string Text)
        {
            StreamWriter File = new StreamWriter(filename);
            File.Write(Text);
            File.Close();
        }

        static string Readfile(string filename)
        {
            StreamReader File = new StreamReader(filename);
            string temp = File.ReadToEnd();
            File.Close();
            return (temp);
        }
    }
}