static void Main(string[] args)
{
const string UN = "admin";
const string PW = "123456";
string usename, password;
int i=0;
while (i <=3)
{
Console .WriteLine ("请输入用户名:");
usename=Console .ReadLine ();
Console .WriteLine ("请输入密码:");
password =Console .ReadLine ();
if ((usename == UN) && (password == PW))
{
Console.WriteLine("登陆成功");
break;
}
else
{
Console.WriteLine("请重新登陆");
i++;
}
}
if (i > 3)
{
Console.WriteLine("当天登陆超过三次，账户被锁定");
}
Console.ReadLine();
}