第一章

namespace Txst_2._1
{
class Animal
{
private Boolean m_sex;
private string m_sound;
public Animal()
{
m_sex = false;
m_sound = "Howl...";
}
public bool Sex
{
get{ return m_sex; }
set { m_sex = value; }

}
public string Sound
{
get { return m_sound; }
set { m_sound = value; }
}
public virtual string Roar()
{
return "Animal" + m_sound;
}
}
class Dog:Animal
{
public Dog()
{
Sex = true;
Sound = "Wow...";
}
public override string Roar()
{
return "Dog:" + Sound;
}
}
class Cat:Animal
{
public Cat()
{
Sound = "Miaow...";
}
public override string Roar()
{
return "Cat:" + Sound;
}
}
class Cow:Animal
{
public Cow()
{
Sound = "Moo...";
}
public override string Roar()
{
return "Cow:" + Sound;
}
}
class Program
{
static void Main(string[] args)
{

Animal animal;
animal = new Dog();
Console.WriteLine(animal.Roar());
animal = new Cat();
Console.WriteLine(animal.Roar());
animal = new Cow();
Console.WriteLine(animal.Roar());
Console.Read();
}
}
}