字符串中提取数字

从字符串中提取数字，有两种方法：

（1）code:

String str ="abc.htm?id=16034$a=343";

            String count=null;
            foreach (char c in str)
            {
                if (c >= '0' && c <= '9')
                {
                    count += c.ToString();
                }
                else
                {
                    if (count != null)
                    {
                        Response.Write(count+"<br/>");
                        count = null;
                    }
                }
            }
            if (count != null)
            {
                Response.Write(count);
                count = null;
            }
(2) regex:
String str = "abc.htm?id=16034$a=343";
            Regex regex = new Regex(@"\d+");
          MatchCollection cc=  regex.Matches(str, 0);
          foreach (Match match in cc)
          {
              Response.Write(match.Value+"<br/>");
          }