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C# 初学
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突然对C#充满了兴趣，于是兴致勃勃的折腾起来。
下面是折腾的过程：
IDE，我选择了vs2017，不过这货的安装选项略多，对于新手来说各种坑。无论如何，选择”.NET桌面开发”即可，其他的全部留空。
然后新建项目，C#项目，控制台项目。
可以开搞了！
总的来说，C#和Java很像 -- 抽象、虚函数、继承、接口等，然而又具有C++的很多特性，如运算符重载！
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks; namespace ConsoleApp1
{
class Go
{
static void Main(string[] args)
{
Cat cat1 = new Cat("a_cat");
Cat cat2 = new Cat("b_cat");
Cat cat3 = new Cat("c_cat"); Console.WriteLine(Animal.Count);
Console.WriteLine(cat1); //测试委托
DoIt doIt = cat1.Speak;
doIt += cat2.Speak; //注意，只要方法签名一致即可连续添加
doIt += cat3.Speak;
doIt += () =>
{
Console.WriteLine("来自Lambda");
};//lambda
doIt(); //测试静态类方法扩展
Dog dog = new Dog("a_dog");
dog.Jump();//这个方法，类似于js的apply或者call //测试隐式转换
Cat cat = dog;
Console.WriteLine(cat);
//测试显式转换
dog = (Dog)cat;
Console.WriteLine(dog); //模拟事件
Client c1 = new Client();
Client c2 = new Client(); Animal.NewAnimal += c1.WantAnimal;
Animal.NewAnimal += c2.WantAnimal; Animal dogq = new Dog("Q-dog"); //测试集合
ArrayList al = new ArrayList();
al.Add(cat1);
al.Add(cat2);
al.Add(cat3);
al.Add(cat2);
Console.WriteLine("ArrayList's count is "+al.Count);
al.Remove(cat2); //只会删除第一个
Console.WriteLine("ArrayList's count is " + al.Count); List<Animal> list = new List<Animal>();
list.Add(cat1);
list.Add(cat2);
list.Add(cat3);
list.Add(cat2);
Console.WriteLine("List's count is " + list.Count); Stack<Animal> stack = new Stack<Animal>();
stack.Push(cat1);
stack.Push(cat2);
stack.Push(cat3);
Console.WriteLine("stack.Peek() = " + stack.Peek() + "; stack.Count = " + stack.Count);
Console.WriteLine("stack.Pop() = " + stack.Pop() + "; stack.Count = " + stack.Count); Queue<Animal> queue = new Queue<Animal>();
queue.Enqueue(cat1);
queue.Enqueue(cat2);
queue.Enqueue(cat3);
Console.WriteLine("queue.First() = " + queue.First() + "; queue.Count = " + queue.Count);
Console.WriteLine("queue.Last() = " + queue.Last() + "; queue.Count = " + queue.Count);
Console.WriteLine("queue.Dequeue() = " + queue.Dequeue() + "; queue.Count = " + queue.Count); Dictionary<int, Animal> dic = new Dictionary<int, Animal>();
dic.Add(, cat1);
dic.Add(, cat2);
dic.Add(, cat3);
Console.WriteLine("dic.Keys = " + dic.Keys + "; dic.Count = " + dic.Count);
Console.WriteLine("自定义扩展dic.Print() = " + dic.PrintKeys() + "; dic.Count = " + dic.Count);
Console.WriteLine("自定义扩展dic.PrintValues() = " + dic.PrintValues() + "; dic.Count = " + dic.Count);
Console.WriteLine(dic); Console.ReadLine();
}
} public delegate void DoIt();//委托，托管一堆方法？！位置，放这里也行？ interface ISpeak
{
void Speak();
}
interface IEat
{
void Eat();
}
class Animal
{
protected string _name;
public static int Count;//用来计数，数一下有多少animal的实例
public delegate void Handler();//事件订阅
public static event Handler NewAnimal; //事件 public Animal() {
++Count;
//通知各位，有新动物来啦
NewAnimal?.Invoke();
}
public Animal(string Name):this()
{
_name = Name;
}
static Animal()
{
Count=;
}
public void setName(string Name)
{
_name = Name;
}
public string getName()
{
return _name ;
}
override public string ToString() //重写父类的
{
return "Animal[_name="+_name+", Count="+Count+"]";
}
}
//狗类，继承自动物，实现接口
class Dog : Animal, ISpeak, IEat
{
public Dog(string Name) : base(Name) { }
public void Eat()
{
Console.WriteLine("我是一只狗，名字：["+base._name+"]，我在吃狗粮！");
} public void Speak()
{
Console.WriteLine("我是一只狗，名字：[" + base._name + "]，汪汪汪！");
}
//定义一个隐式转换
public static implicit operator Cat(Dog dog)
{
return new Cat(dog._name);//new 会改变Animal.Count
}
}
//猫类，继承自动物，实现接口
class Cat : Animal, ISpeak, IEat
{
public Cat(string Name) : base(Name) { }
public void Eat()
{
Console.WriteLine("我是一只猫，名字：[" + base._name + "]，我在吃小鱼干~");
} public void Speak()
{
Console.WriteLine("我是一只猫，名字：[" + base._name + "]，喵~");
} //定义一个显式转换
public static explicit operator Dog(Cat cat)
{
return new Dog(cat._name);//new 会改变Animal.Count
}
}
//静态类 扩展方法
static class DogJump
{
public static void Jump(this Dog dog)
{
Console.WriteLine(dog + " is jumping...");
}
public static string PrintKeys(this Dictionary<int, Animal> dic)
{
var s="";
foreach (var item in dic.Keys)
{
s += item;
s += ", ";
}
return s;
}
public static string PrintValues(this Dictionary<int, Animal> dic)
{
var s = "";
foreach (var item in dic.Values)
{
s += item;
s += ", ";
}
return s;
}
} //定义一个客户类
class Client
{
public void WantAnimal()
{
Console.WriteLine("Great! I wanna see it!");
}
} }
