S2 深入.NET平台和C#语言 第三章 课上练习

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Collections;namespace 深入.NET平台第三章_课上{    class Program    {        /*            * 自动扩容：            * 如果结合中一个元素都没有的话，Capacity为0，            * 如果集合中出现第一个元素，分配4个空间，            * 如果出现第5个元素的时候，可以容纳8个元素，            * 每次扩容会扩成上次的2倍            *             *             * 1.1那么，系统怎么知道何时扩容？在哪个方法中进行了扩容。            * 解析：Add方法扩容，容量不够的时候            *             */                static void Main(string[] args)        {            int[] nums = new int[3];            ArrayList ss = new ArrayList();            ss.Add(1);            ss.Add(2);            ss.Add(2);            ss.Add(3);            ss.Add(4);            foreach (Object item in list)            {                Console.WriteLine(item);            }            Console.WriteLine(ss.Capacity + "   容量");  //  6            Console.WriteLine(ss.Count + " 真正存储元素个数");//5            ArrayList engineers = new ArrayList(){            new student(){  Name="王",Author="hh",Price=20   },             new student(){  Name="王高达",Author="苏苏",Price=40   },              new student(){  Name="王地方",Author="恩恩",Price=390   },            };            Console.WriteLine(engineers.Count.ToString());           // ForeachTest();            student student1 = new student("如果蜗牛有爱情", "丁墨", 50);            student student2 = new student("花千骨", "果儿", 60);            student student3 = new student("盗墓笔记", "南派三叔", 70);            list.Add(student1);            list.Add(student2);            list.Add(student3);            foreach (student item in list)            {                Console.WriteLine(item.Name);            }   Console.WriteLine("===================修改===============");   foreach (student item in list)   {       if (item.Name.Equals("如果蜗牛有爱情"))       {           item.Name = "他来了，请闭眼";           break;       }   }            foreach (student item in list)            {                Console.WriteLine(item.Name);            }            //按索引删除            Console.WriteLine("===================================我是高贵的分界线================");            list.RemoveAt(0);            foreach (student item in list)            {                Console.WriteLine(item.Name);            }            //按对象删除              list.Remove("花千骨");            Console.WriteLine("===================================我是高贵的分界线================");                      foreach (student item in list)            {                Console.WriteLine(item.Name);            }            //清空所有            Console.WriteLine("===================================我是高贵的分界线================");            list.Clear();            foreach (student item in list)            {                               Console.WriteLine(item.Name);            }            //对象初始化器            student stu = new student() { Name = "苏琳琳" };            ArrayList l = new ArrayList()             {                stu            };            //双列集合            Hashtable table = new Hashtable();            table.Add("CBC", "建设银行");            table.Add("ABC", "中国农业银行");            table.Add("ICBC", "工商银行");            //方式一：遍历 根据key拿到 VaLue,Next key的 集合            foreach (string key in table.Keys)            {                Console.WriteLine("key是："+key);                //value 如何通过key  拿到 value!                 //索引器                object value = table[key];                    Console.WriteLine("value是："+value.ToString());            }            Console.WriteLine("=================================================");            //方式二：直接遍历value            foreach (string value in table.Values)            {                Console.WriteLine(value);            }            //03 key和value一次遍历一个项目===（key+value）            foreach (DictionaryEntry item in table)            {                Console.WriteLine(item.Key+"  "+item.Value);            }            Console.ReadLine();        }        static ArrayList list = new ArrayList();        public static void ForeachTest()        {            student student1 = new student("如果蜗牛有爱情", "丁墨", 50);            student student2 = new student("花千骨", "果儿", 60);            student student3 = new student("盗墓笔记", "南派三叔", 70);            list.Add(student1);            list.Add(student2);            list.Add(student3);             foreach(student item in list){                 Console.WriteLine(item.Name);               }        }        }}