多态-抽象类
抽象类：
当父类中的方法不知道如何去实现的时候，可以考虑将父类写成抽象类，将方法写成抽象方法。
关键字abstract，抽象方法没有方法体
1.抽象类
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6 7 namespace _11_抽象类 8 { 9 class Program 10 { 11 static void Main(string[] args) 12 { 13 //狗狗会叫 猫咪会叫 14 15 Animal a = new Cat();//new Dog(); 16 a.Bark(); 17 18 Console.ReadKey(); 19 } 20 } 21 22 public abstract class Animal 23 { 24 25 public virtual void T() 26 { 27 Console.WriteLine("动物有声明"); 28 } 29 30 private int _age; 31 32 public int Age 33 { 34 get { return _age; } 35 set { _age = value; } 36 } 37 38 public Animal(int age) 39 { 40 this.Age = age; 41 } 42 public abstract void Bark(); 43 public abstract string Name 44 { 45 get; 46 set; 47 } 48 49 // public abstract string TestString(string name); 50 51 52 public Animal() 53 { 54 55 } 56 //public void Test() 57 //{ 58 // //空实现 59 //} 60 } 61 62 63 public abstract class Test : Animal 64 { 65 66 } 67 68 public class Dog : Animal 69 { 70 // public abstract void Test(); 71 72 73 public override void Bark() 74 { 75 Console.WriteLine("狗狗旺旺的叫"); 76 } 77 78 public override string Name 79 { 80 get 81 { 82 throw new NotImplementedException(); 83 } 84 set 85 { 86 throw new NotImplementedException(); 87 } 88 } 89 90 //public override string TestString(string name) 91 //{ 92 // //throw new NotImplementedException(); 93 //} 94 } 95 96 public class Cat : Animal 97 { 98 public override void Bark() 99 { 100 Console.WriteLine("猫咪喵喵的叫"); 101 } 102 103 public override string Name 104 { 105 get 106 { 107 throw new NotImplementedException(); 108 } 109 set 110 { 111 throw new NotImplementedException(); 112 } 113 } 114 } 115 }
2.练习
1 using System; 2 3 namespace Practice_多态_抽象类 4 { 5 class Program 6 { 7 static void Main(string[] args) 8 { 9 Sharp s = new Circle(6); 10 double perimeter=s.GetPerimeter(); 11 double area=s.GetArea(); 12 Sharp h = new Square(1, 2); 13 double area1= h.GetArea(); 14 double preimeter1 = h.GetPerimeter(); 15 Console.WriteLine("圆的面积是{0}，周长是{1}，矩形的面积是{2}，周长是{3}", area, perimeter, area1, preimeter1); 16 Console.ReadKey(); 17 18 19 } 20 } 21 } 22 23 24 25 26 using System; 27 using System.Collections.Generic; 28 using System.Linq; 29 using System.Text; 30 using System.Threading.Tasks; 31 32 namespace Practice_多态_抽象类 33 { 34 public abstract class Sharp 35 { 36 public abstract double GetArea(); 37 public abstract double GetPerimeter(); 38 } 39 40 } 41 42 43 44 using System; 45 using System.Collections.Generic; 46 using System.Linq; 47 using System.Text; 48 using System.Threading.Tasks; 49 50 namespace Practice_多态_抽象类 51 { 52 public class Circle:Sharp 53 { 54 private double _r; 55 public double R 56 { 57 get { return _r; } 58 set { _r = value; } 59 } 60 public Circle(double r) 61 { 62 this.R = r; 63 } 64 public override double GetArea() 65 { 66 return Math.PI * this.R * this.R; 67 } 68 public override double GetPerimeter() 69 { 70 return 2 * Math.PI * this.R; 71 } 72 } 73 } 74 75 76 77 78 using System; 79 using System.Collections.Generic; 80 using System.Linq; 81 using System.Text; 82 using System.Threading.Tasks; 83 84 namespace Practice_多态_抽象类 85 { 86 public class Square:Sharp 87 { 88 private double _height; 89 public double Height 90 { 91 get { return _height; } 92 set { _height = value; } 93 } 94 private double _with; 95 public double With 96 { 97 get { return _with; } 98 set { _with = value; } 99 } 100 public Square(double with,double height) 101 { 102 this.With = with; 103 this.Height = height; 104 } 105 106 public override double GetPerimeter() 107 { 108 return this._height * 2 + this._with * 2; 109 } 110 public override double GetArea() 111 { 112 return this._with * this._height; 113 } 114 } 115 }
3.练习
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6 7 namespace _12_抽象类 8 { 9 class Program 10 { 11 static void Main(string[] args) 12 { 13 //使用多态求矩形的面积和周长以及圆形的面积和周长 14 Shape shape = new Square(5, 6); //new Circle(5); 15 double area = shape.GetArea(); 16 double perimeter = shape.GetPerimeter(); 17 Console.WriteLine("这个形状的面积是{0},周长是{1}", area, perimeter); 18 Console.ReadKey(); 19 20 } 21 } 22 23 public abstract class Shape 24 { 25 public abstract double GetArea(); 26 public abstract double GetPerimeter(); 27 } 28 public class Circle : Shape 29 { 30 31 private double _r; 32 public double R 33 { 34 get { return _r; } 35 set { _r = value; } 36 } 37 38 public Circle(double r) 39 { 40 this.R = r; 41 } 42 public override double GetArea() 43 { 44 return Math.PI * this.R * this.R; 45 } 46 47 public override double GetPerimeter() 48 { 49 return 2 * Math.PI * this.R; 50 } 51 } 52 public class Square : Shape 53 { 54 private double _height; 55 56 public double Height 57 { 58 get { return _height; } 59 set { _height = value; } 60 } 61 62 private double _width; 63 64 public double Width 65 { 66 get { return _width; } 67 set { _width = value; } 68 } 69 70 public Square(double height, double width) 71 { 72 this.Height = height; 73 this.Width = width; 74 } 75 76 public override double GetArea() 77 { 78 return this.Height * this.Width; 79 } 80 81 public override double GetPerimeter() 82 { 83 return (this.Height + this.Width) * 2; 84 } 85 } 86 87 }
4.电脑、移动硬盘、U盘、MP3
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6 7 namespace _13_电脑_移动硬盘_U盘_MP3 8 { 9 class Program 10 { 11 static void Main(string[] args) 12 { 13 //用多态来实现 将 移动硬盘或者U盘或者MP3插到电脑上进行读写数据 14 15 //MobileDisk md = new MobileDisk(); 16 //UDisk u = new UDisk(); 17 //Mp3 mp3 = new Mp3(); 18 //Computer cpu = new Computer(); 19 //cpu.CpuRead(u); 20 //cpu.CpuWrite(u); 21 //Console.ReadKey(); 22 23 MobileStorage ms = new UDisk();//new Mp3();//new MobileDisk();//new UDisk(); 24 Computer cpu = new Computer(ms); 25 //cpu.Ms = ms; 26 cpu.CpuRead(); 27 cpu.CpuWrite(); 28 //Computer cpu = new Computer(); 29 //cpu.CpuRead(ms); 30 //cpu.CpuWrite(ms); 31 Console.ReadKey(); 32 33 } 34 } 35 36 37 ///38 /// 抽象的父类 39 /// 40 public abstract class MobileStorage 41 { 42 public abstract void Read(); 43 public abstract void Write(); 44 } 45 46 47 public class MobileDisk : MobileStorage 48 { 49 public override void Read() 50 { 51 Console.WriteLine("移动硬盘在读取数据"); 52 } 53 public override void Write() 54 { 55 Console.WriteLine("移动硬盘在写入数据"); 56 } 57 } 58 public class UDisk : MobileStorage 59 { 60 public override void Read() 61 { 62 Console.WriteLine("U盘在读取数据"); 63 } 64 65 public override void Write() 66 { 67 Console.WriteLine("U盘在写入数据"); 68 } 69 } 70 public class Mp3 : MobileStorage 71 { 72 public override void Read() 73 { 74 Console.WriteLine("MP3在读取数据"); 75 } 76 77 public override void Write() 78 { 79 Console.WriteLine("Mp3在写入数据"); 80 } 81 82 public void PlayMusic() 83 { 84 Console.WriteLine("MP3自己可以播放音乐"); 85 } 86 } 87 88 89 90 public class Computer 91 { 92 private MobileStorage _ms; 93 94 public MobileStorage Ms 95 { 96 get { return _ms; } 97 set { _ms = value; } 98 } 99 public void CpuRead() 100 { 101 Ms.Read(); 102 } 103 104 public void CpuWrite() 105 { 106 Ms.Write(); 107 } 108 public Computer(MobileStorage ms) 109 { 110 Ms = ms; 111 } 112 } 113 }