程序代码：

            Console.WriteLine("请输入一个整数：");
            int num = int.Parse(Console.ReadLine());
            string temp = "";
            while (num > 0)
            {
                temp += num % 2;
                num /= 2;
            }
            for (int i = temp.Length - 1; i >= 0; i-- )
                Console.Write(temp[i]);