static void Main(string[] args)
{
//Father ff = new Father("aa", 99, "ab");
//Son son = new Son("张三", 1000, "AB");
//Father fat = new Father("张三", 10000, "O");
//Son son = new Son("ZhangsanSon", 1000, "AB");
//M1(son);
//Console.ReadKey();
//object obj = new Son();
//里氏替换原则，要的是一个父类类型对象，给的是一个子类类型对象。
//里氏替换原则反过来是不行的。
Father ff = new Son("李四", 99999, "A");
//ff.LastName;
//Father ff = new Father();
//Son son = new Son();
object o = new Father("aa", 9999, "A");
//错误！！！！
//Son ss = new Father("王五", 999999, "AB");
}
static void Main(string[] args)
{
Son son = new Son("张三", 1000, "AB");
}
static void Main(string[] args)
{
Son son = new Son("张三", 1000, "AB");
}