C#Protected和多态

Protected在基类中界说后，能被派生类调用，但是不能被其他类调用。

virtual在基类中界说后，在派生类中能被重写。
usingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespace承继
{classVertebrate
{protectedstringspine;//受维护的字段privatedoubleweigth;privatedoubletemperature;publicdoubleWeigth

{set{if(value<0)
{
weigth=0;
}else{
weigth=value;
}
}get{returnweigth;}
}publicdoubleTemperature
{set{if(value<0)
{
temperature=0;
}else{
temperature=value;
}
}get{returntemperature;}
}publicVertebrate()
{
spine=”脊柱”;
weigth=0;
temperature=0;
}publicvirtualvoidBreate()//虚办法{
Console.WriteLine(“呼吸”);
}publicvoidSleep()
{
Console.WriteLine(“睡觉”);
}
}
}
usingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespace承继
{classProgram
{staticvoidMain(string[]args)
{
Vertebratevertebrate=newVertebrate();
vertebrate.spine1=”脊柱”;//public的就能被直接调用Mammalmammal=newMammal();
Fishfish=newFish();
Animalanimal=newAnimal();
Console.WriteLine(“我是一只哺乳动物”);
mammal.Scukle();
animal.Breate();
mammal.Breate();
fish.Breate();
mammal.Sleep();
mammal.Message();
}
}classFish:Vertebrate
{publicoverridevoidBreate()//重写基类中的虚办法{
Console.WriteLine(“用鳃呼吸”);
}
}classAnimal:Vertebrate
{
}classMammal:Vertebrate//派生类：基类{privatestringarms;privatestringlegs;privateintage;publicintAge
{set{age=value;}get{returnage;}
}publicMammal()
{
arms=”前肢”;
legs=”后肢”;
Age=0;
Weigth=10;
Temperature=37;
}publicvoidScukle()
{
Console.WriteLine(“哺乳”);
}publicoverridevoidBreate()
{
Console.WriteLine(“用肺呼吸”);
}publicvoidMessage()
{
Console.WriteLine(“体重：{0}”,Weigth);
Console.WriteLine(“年龄：{0}”,Age);
Console.WriteLine(“体温：{0}”,Temperature);
Console.WriteLine(“我有{0}和{1}”,arms,legs);
}
}
}