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

namespace Kolokwium_algorytmy
{
    class Program
    {
        public string zadanie1()
        {
            Random random = new Random();
            Regex regex = new Regex(@"^[A-Z]{3}[0-9]$");
            string litery = "ABCDEFGHIJKLMNOPQRSTUWXYZ";
            string cyfry = "1234567890";
            string napis = null;
            int n = random.Next(0, 10);
            int kolejnosc = random.Next(0, 2);
            if (kolejnosc == 0)
            {
                for (int i = 0; i < 3; i++)
                {
                    napis += litery[random.Next(0, litery.Length)];
                }
                for (int j = 0; j < n; j++)
                {
                    napis += cyfry[random.Next(0, cyfry.Length)];
                }
                return napis;
                Console.WriteLine(" ", regex.IsMatch(napis));
            }
            else
            {
                for(int i = 0; i < n; i++)
                {
                    napis += cyfry[random.Next(0, cyfry.Length)];
                }
                for (int j = 0; j < 3; j++)
                {
                    napis += litery[random.Next(0, litery.Length)];
                }
                return napis;
                Console.WriteLine(" ", regex.IsMatch(napis));
            }
            return napis;
        }
        static void Main(string[] args)
        {
            Program obiekt = new Program();
            Console.WriteLine(obiekt.zadanie1());
            Stos obiekt2 = new Stos(6);
            Console.Write(obiekt2.zadanie4());
            Console.WriteLine(Regex.IsMatch(obiekt.zadanie2(), (@"^[A-Z]{3}[0-9]$"));
            Console.ReadKey();

        }
    }

        class Stos
        {
            int?[] array;
            int number = 0;
            public Stos(int size)
            {
                array = new int?[size];
            }
            public Stos(Stos s)
            {
                int?[] array2;
                array2 = new int?[s.zwrocTablice.Length * 2];
                for(int i = 0; i < array2.Length; i++)
                {
                    array2[i] = array[i];
                }
            }

            public void Add(int number)
            {
                if (number != array.Length)
                {
                    array[number++] = number;
                }
            }

            public int? Peek()
            {
                int? back = null;
                if (number != 0)
                {
                    back = array[--number];
                }
                return back;
            }
            public int?[] zwrocTablice
            {
                get
                {
                    return array;
                }
            }
            public string zadanie4()
            {
                Random random = new Random();
                string napis2 = "abcdefghijklmnopqrstuwxz";
                string zadanie4 = null;
                for(int i = 0; i < 8; i++)
                {
                    zadanie4 += napis2[random.Next(0, napis2.Length)];
                }
                return zadanie4;
            }
        }


        class Queue
        {
            int?[] array;
            int head = 0, tail = 0, size = 0;
            public Queue(int size)
            {
                array = new int?[size];
            }

            public void Enque(int number)
            {
                if (size != array.Length)
                {
                    size++;
                    array[tail++] = number;
                    tail = tail % array.Length;
                }
            }

            public int? Deque()
            {
                int? back = null;
                if (size != 0)
                {
                    back = array[head];
                    array[head++] = null;
                    size--;
                    head = head % array.Length;

                }
                return back;
            }
            public int dodaj(int n)
            {
            Random random = new Random();
            int wartosc;
            for(int i = 0; i < n; i++)
            {
                wartosc = random.Next(0, 10);
            }
            return n;
            }
        }
    }