using System;
public class Program
{
public static void Main()
Console.Write("请输入:");
char c=char.Parse(Console.ReadLine());
if(c>='a'&&c<='z')
Console.WriteLine("小写字母{0}转为大写字母{1}",c,Convert.ToChar(c+32));
else if(c>='A'&&c<='Z')
Console.WriteLine("大写字母{0}转为小写字母{1}",c,Convert.ToChar(c-32));
else
Console.WriteLine("{0}不是字母,不作处理",c);
Console.ReadLine();
}