C#递归

class Program
    {
        public int jiecheng(int i)
        {
            if (i == 1)//函数停止继续调用的条件，函数的出口
            {
                return i;
            }
            int sum = i * jiecheng(i-1);
            //i=5
            //int sum = 5*jiecheng(4);
            //int sum = 5*(4*jiecheng(3));
            //int sum = 5*(4*(3*jiecheng(2)));
            //int sum = 5*(4*(3*(2*jiecheng(1))));
            //int sum = 5*(4*(3*(2*1)));

            return sum;
        }
        public double tz(double a)
        {
            double sum = 0;
                if(a==1)
                {
                    return 2;
                }
               sum= Math.Pow(2, a);
            return sum;
        }
        

        /// <summary>
        /// 求生兔子，输入几个月之后
        /// </summary>
        /// <param name="i"></param>
        /// <returns></returns>
        public int abc(int i)
    {
    int sum=0;
    if (i == 1)
    {
        return 2;
    }
    sum = i * 2 * abc(i - 1);
    return sum;
    }

        struct jiegouti
        {
            public string name;
            public int piao;
        }

        public void xuan()
        {
            ArrayList al=new ArrayList();
            jiegouti jgt1=new jiegouti();
            jiegouti jgt2 = new jiegouti();
            jiegouti jgt3 = new jiegouti();
            jiegouti jgt4 = new jiegouti();
            jiegouti jgt5= new jiegouti();
            jiegouti jgt6 = new jiegouti();
            for (int i = 0; i < 20;i++ )
            {
                Console.WriteLine("请投票（张三1，李四2，王五3，赵六4，冯七5）");
                int a = int.Parse(Console.ReadLine ());
                switch (a)
                {
                    case 1:
                        jgt1.piao++;
                        break;
                    case 2:
                        jgt2.piao++;
                        break;
                    case 3:
                        jgt3.piao++;
                        break;
                    case 4:
                        jgt4.piao++;
                        break;
                    case 5:
                        jgt5.piao++;
                        break;
                    default :
                        jgt6.piao++;
                        break;
                }
            }
            jgt1.name = "张三";
            al.Add(jgt1);
            jgt2.name = "李四";
            al.Add(jgt2);
            jgt3.name = "王五";
            al.Add(jgt3);
            jgt4.name = "赵六";
            al.Add(jgt4);
            jgt5.name = "冯七";
            al.Add(jgt5);
            jgt6.name = "废票";
            al.Add(jgt6);
            
            //冒泡排序
            for(int i=0;i<6;i++)
            {
                for (int j = i; j< 5;j++ )
                {
                    jiegouti b=(jiegouti )al[i];
                    jiegouti b1 = (jiegouti )al[j+1];
                    jiegouti b2 = new jiegouti();

                    if (b.piao < b1.piao)
                    {
                        ArrayList zhong = new ArrayList();
                        b2.name = "";
                        b2.piao = 0;
                        zhong.Add(b2 );

                        zhong[0] = al[i];
                        al[i] = al[j + 1];
                        al[j + 1] = zhong[0];
                    }
                }

               
            }

            jiegouti shuchu = new jiegouti();
            shuchu = (jiegouti)al[0];
            Console.WriteLine(shuchu.name + shuchu.piao);
            Console.WriteLine("废票" + jgt6.piao);
        }



        static void Main(string[] args)
        {
            //Program hanshu = new Program();
            //Console.Write("请输入一个正整数：");
            //int a = int.Parse(Console.ReadLine());
            //Console.WriteLine("阶乘的结果是："+hanshu.jiecheng(a));
            //Console.ReadLine();


            //编写递归函数求 2*4*6*……*(2n) 的结果
            //Program sh = new Program();
            //Console.WriteLine("输入n");
            //int sd = int.Parse(Console.ReadLine());
            //int sda = sh.abc(sd);
            //Console.WriteLine(sda);
            //Console.ReadLine();



           //有雌雄一对兔子，每过一个月便可繁殖雌雄各一的一对小兔子。
           //问过n个月后共有多少对兔子？

            //Console.Write("请输入第几个月：");
            //double mm = double.Parse(Console.ReadLine());
            //Program ss = new Program();
            //double  aa= ss.tz(mm);
            //Console.WriteLine("兔子的总数是："+aa);
            //Console.ReadLine();



            //数组 or集合 or结构体
            //5个候选人竞选班长：张三，李四，王五，赵六，冯七
            //班级中共有20人，20人轮流投票
            //只要不是1~5之内的视为作废   统计
            //最后要知道谁的票数最多，当选班长
            Program hanshu = new Program();
            hanshu.xuan();
            Console.ReadLine();












            //Program zdy = new Program();
            //Console.WriteLine("请输入你想知道第几个月后的兔子数：");
            //int a = int.Parse(Console.ReadLine());
            //Console.WriteLine(zdy.tz(a));
            //Console.ReadLine();


            //2的3次方
            //Console.WriteLine(Math.Pow(2,3));
            //Console.ReadLine();





        }
    }