Console.WriteLine("请输入截止数字？退出请输入y");

            string input = Console.ReadLine();

            int n = Convert.ToInt32(input);

            int count = ; //计数

            for (int i = ; i <= n; i++)

            {

                string str = i.ToString();//要匹配的字符串

                string pattern=""; //要匹配的正则表达式模式

                MatchCollection matches = Regex.Matches(str, pattern);  //正则表达式匹配验证

                count += matches.Count;  //获得匹配数量，加到计数上，

                //foreach (Match NextMatch in matches) //遍历获得数量也行，不过效率低

                //{

                //    count++;

                //}

            }

            Console.WriteLine("在0-{0}中1出现了"+count+"次",input);