//Write a program and ask the user to enter 5 numbers. 

//If a number has been previously entered, display an error message and ask the user to re-try. 

//Once the user successfully enters 5 unique numbers, sort them and display the result on the console.

​

using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        List<int> userNumbers = new List<int>();

​

        while(userNumbers.Count < 5)

        {

            Console.Write("Enter a number: ");

​

            int userInput = int.Parse(Console.ReadLine());

            if(userNumbers.Contains(userInput))

            {

                Console.WriteLine("Number is not unique, add a different number!!");

            }

​

            else

            {

                userNumbers.Add(userInput);

            }

         }

​

         int[] result = userNumbers.ToArray();

         Array.Sort(result);

         Console.WriteLine();        

​

         foreach(var number in result)

         {

             Console.Write(number);

         }

         Console.ReadLine();

    }

}