秋风雅居

using System;
using System.Text.RegularExpressions;

public class Test
{
    static void Main()
    {
        string s = GetTest("sdfdf");
        s = GetTest("334324#");
        s = GetTest("34324");
    }

    static string GetTest(string s)
    {
        if (Regex.Match(s, "^\\d+$").Success)
        {
            return "数字";
        }
        else if (Regex.Match(s, "^[a-zA-Z]+$").Success)
        {
            return "字符";
        }
        else
        {
            return "其他结果";
        }
    }
}