ArrayList arrayList = new ArrayList();//类的初始化arrayList.Add("小蚊子");//往arrayList中添加arrayList.Add(12);arrayList.Add(new person("小郭", 20, '女'));for (int i = 0; i < arrayList.Count; i++)//遍历 arrayList的数组，arrayList.Count为数组的长度
            {if (arrayList[i] is person)//用is判断arrayList[i] 是否能转化为 person类
                {((person)arrayList[i]).SayHi();//如果能转换为person，强转，调用person中SayHi方法
                }else{Console.WriteLine(arrayList[i]);//输出arrayList[i]
                }}Console.ReadKey();}}public class person{public person(string name, int age, char sex){this.Name = name;this.Age = age;this.Sex = sex;}private string _name;public string Name{get { return _name; }set { _name = value; }}private int _age;public int Age{get { return _age; }set { _age = value; }}private char _sex;public char Sex{get { return _sex; }set { _sex = value; }}public void SayHi(){Console.WriteLine("{0}岁的{1}在软件学院是最纯洁的{2}学生", Age, Name, Sex);}}
}

           ArrayList arrayList = new ArrayList();int[] nums = new int[] { 3, 4, 5, 6, 7, 9, 8, 8 };arrayList.InsertRange(0, nums);//在指定索引位置插入一个数组int num = arrayList.LastIndexOf(9);//查找出元素最后一次出现的位置arrayList.Remove(9);//移除集合中某个元素arrayList.RemoveAt(2);//给个索引,移除这个索引对应的元素arrayList.RemoveRange(4, 2);//从指定索引位置开始移除,移除几个元素arrayList.Reverse();//集合反转arrayList.Sort();//排序

           Hashtable hashTable = new Hashtable();//实例化化 hashTablehashTable.Add(1, "小杨");//在 hashTable中插入键值为1，值为小杨数据hashTable.Add(2, "老苏");hashTable.Clear();//清空 hashTable中的值bool result = hashTable.Contains(1);//判断 hashTable中是否包含键值为1的数据hashTable.Remove("小杨");//移除小杨// hashTable[key];//这个key对应的值int num = hashTable.Count;//哈希表的长度

            List<int> num = new List<int>();//实例化numint max, min, sum;for (int i = 0; i < 100; i++)//在num中添加字段
            {num.Add(i);}sum = num.Sum();//计算num的和max = num.Max();//最大值min = num.Min();//最小值double avg = num.Average();//求平均值

           Dictionary<char, char> dic = new Dictionary<char, char>();string newStr = "";for (int i = 0; i < Jian.Length; i++){dic.Add(Jian[i], HXW[i]);}for (int i = 0; i < str.Length; i++){if (dic.ContainsKey(str[i])){newStr += dic[str[i]];}else{newStr += str[i];}}Console.WriteLine(newStr);Console.ReadKey();