夜来无聊

    class Program
    {
        static void Main(string[] args)
        {
            Thread th = new Thread(Print);
            th.Start();
            Console.Read();
        }
        static bool has;
        static string code;
        static bool stop;
        static int a;
        static Random rnd = new Random((int)DateTime.Now.Ticks);
        public static void Print()
        {
            while (a < 10)
            {
                has = true;
                if (has == true && stop == false)
                {
                    code = Give();
                    Console.WriteLine(code);
                    has = false;
                }
                a++;
                if (a == 10)
                {
                    stop = true;
                }
            }
        }
        public static string Give()
        {
            int First = (int)'a';
            int Last = (int)'z';
            char[] chr = new char[4];
            for (int i = 0; i < 4; i++)
            {
                int k = rnd.Next(First, Last);
                chr[i] = (char)k;
            }
            string str = new string(chr);
            return str;
        }
    }