1st attempt

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

namespace WHILE_OneToHundred
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter a number in the range [1...100]: ");
            int num = int.Parse(Console.ReadLine());


            while (true)
            {
                if (num >= 1 && num <= 100)
                {
                    Console.WriteLine("The number is: " + num);
                }

                else if (num < 1 || num > 100)
                {
                    Console.WriteLine("Invalid number!");
                    Console.WriteLine("Enter a number in the range [1...100]: ");
                    Console.ReadLine();
                }
                break;
            }

        }
    }
}