例题：输入学生的各项资料，然后根据学生的分数，重新排序。重新复习结构体，集合，数组，for循环，冒泡排序，水平符的使用。

 class Program

    {

        struct student     //定义一个student的结构体

        {

            public string name;   //基本格式

            public int code;

            public int age;  

           public int fenshu;

        }

        static void Main(string[] args)

        {

            while (true)

            {   

              ArrayList al = new ArrayList();  //定义一个新的集合

                Console.Write("请输入人数：");

                int renshu = Convert.ToInt32(Console .ReadLine ());

                for (int i = 0; i < renshu ; i++)

                {

                                       student r = new student();   //定义一个student类型r的变量，可以存储数值

                    Console.Write("请输入学生姓名：");

                    r.name = Console.ReadLine();

                    Console.Write("请输入学生学号：");

                    r.code = Convert.ToInt32(Console.ReadLine());

                    Console.Write("请输入学生年龄：");

                    r.age = Convert.ToInt32(Console.ReadLine());

                    Console.Write("请输入学生分数：");  

                   r.fenshu = Convert.ToInt32(Console.ReadLine());

                    al.Add(r);     //把r的值代入到al这个集合里

              }

                for (int i = 0; i < renshu; i++)      //按分数冒泡排序

               {

                    for (int j = i; j < renshu -1; j++)

                    {

                        if (((student)al[i]).fenshu<((student)al[j+1]).fenshu  )   //好好看这句代码，不好理解，student类型里从al里取值

                        {   

                          student  zhong ;

                            zhong = (student)al[i] ;

                            al[i] = al[j + 1];

                            al[j + 1] = zhong;

                        }  

                   }  

               }  

               Console.WriteLine("排后学生顺序");

                for (int i = 0; i < renshu ; i++)

                {                                                     //水平符输出

                    Console.WriteLine("姓名"+((student)al[i]).name+" 学号"+((student)al[i]).code +" 分数"+((student)al[i]).fenshu  +" 年龄"+((student)al[i]).age  );

                }

            }  

           Console.ReadLine();