static void Modify(Person p)
{
if(p != null)
{
p.Name = "new name " + p.Name;
}
}
static void Main(string []args)
{
/*
string str1 = "aaaa";
string str2 = "bbbb";
Swap(ref str1,ref str2);
Console.WriteLine("str1:{0}, str2:{1}",str1,str2);
*/
Person p = new Person( ) ;
p.Name = "zhangsan";
Modify(p);
Console.WriteLine(p.Name);
}