定义动物类Animal，在类中定义字段·属性和虚拟方法；由基类Anima创建派生类Dog，Cat，在派生类中实现方法重载；在程序中实例化类的对象并调用类的方法。
1.Animal.cs文件：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication3
{
class Animal
{
private bool m_sex;
private int m_age;
public bool Sex
{
get
{
return m_sex;
}
set
{
m_sex = value;
}
}
public int Age
{
get
{
return m_age;
}
set
{
m_age = value;
}
}
public Animal()
{
m_sex = false;
}
public virtual void Introduce()
{
if (Sex == true)
Console.WriteLine("This is a male Animal!");
else
Console.WriteLine("This is a female Animal!");
}
}
class Dog:Animal
{
public Dog()
{
Sex = true;
}
public override void Introduce()
{
if (Sex == true)
Console.WriteLine("This is a male Dog!");
else
Console.WriteLine("This is a female Dog!");
}
}
class Cat:Animal
{
public override void Introduce()
{
if (Sex == true)
Console.WriteLine("This is a male Cat!");
else
Console.WriteLine("This is a female Cat!");
}
}
}
2.实例化调用：
class Program
{
static void Main(string[] args)
{
Animal animal = new Animal();
animal.Introduce();
Animal dog = new Dog();
dog.Introduce();
Animal cat = new Cat();
cat.Introduce();
}
}
3.结果：
