C#课堂笔记-2013-10-25

省纸了。。。。

 

课件内容：

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所有类型的基类型，System.Object

Class Employee{}//隐式

Class Employee:System.Object{}//显式

等效

System.Object的公有方法

Equals()//两个object实例是否相等

GetHashCode()//

ToString()//返回类型全名this.GetType().FullName.ToString

GetType()//

ReferenceEquals()//是否相同实例

 

 

 

 

 

 

此段代码关于上映射(up cast)和下映射(down cast)

is 和 as 的用法

A->B->C->D    从爷爷到子孙

B(C\D) is A

A is not B(CD)

 

 

 

using System;
class Employee { }
class Manager : Employee { }
class App
{
    public static void Main()
    {
        Manager m = new Manager();
        PromoteEmployee(m);
        DateTime newYears = new DateTime(2004, 1, 1);
        PromoteEmployee(newYears);
    }
    public static void PromoteEmployee(Object o)
    {
        Employee e = (Employee)o;
    }
}

using相当于java的import，VB的imports

using CNProduct =CompanyName.Product;//using添加别名

 

C#中的Enum，目测和C++一样。(Char以外的任何类型都可，默认是int32)

枚举隐式派生自System.Enum.

System.enum继承自system.ValueType

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第二次实验（什么时候有第一次？）：

课下作业么：

tips：

 

 

打开英文文本文件，count单词数（空格，标点（那么多种标点怎么if））。统计单词出现频率（所有的？动态数组？）

 

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace StreamWrite{
    class Program    {
/*        static void Main(string[] args)        {
            try{
                FileStream aFile = new FileStream("Log.txt", FileMode.OpenOrCreate);
                StreamWriter sw = new StreamWriter(aFile);
                bool truth = true;                // Write data to file.
                sw.WriteLine("Hello to you.");
                sw.WriteLine("It is now {0} and things are looking good.",                    DateTime.Now.ToLongDateString());
                sw.Write("More than that,");
                sw.Write(" it's {0} that C# is fun.", truth);
                sw.Close();            
            }catch (IOException ex)            {
                Console.WriteLine("An IOException has been thrown!");
                Console.WriteLine(ex.ToString());
                Console.ReadLine();
                return;
            }
        }
的*/
        //读取文件，StreamReader对象
        static void Main(string[] args)
        {
            string strLine;
            try
            {
                FileStream aFile = new FileStream("Log.txt", FileMode.Open);
                StreamReader sr = new StreamReader(aFile);
                strLine = sr.ReadLine();            //Read data in line by line 一行一行的读取      
                while (strLine != null)
                {
                    Console.WriteLine(strLine);
                    strLine = sr.ReadLine();
                }
                sr.Close();
            }
            catch (IOException ex)
            {
                Console.WriteLine("An IOException has been thrown!");
                Console.WriteLine(ex.ToString());
                Console.ReadLine();
                return;
            }
        }

    }
}

 

详细操作需要

System.IO.StreamReader 的 10个构造函数、20个方法、1个字段和3个属性

 

 

百度搜索 “ C# 读取 文件 统计 单词”