Practic 3.5

using System;

namespace Practice
{
    class Program1
    {
        static void Main(string[] args)
        {
            int n = 5;
            for (int i = 0; i < 5; ++i)
            {
                for (int j = 0; j < n; ++j)
                {
                    Console.Write($"{j} ");
                }
                Console.WriteLine();
                Console.WriteLine();
                n--;
            }
            Console.ReadKey();
        }
    }
}