0312数组

随机数类random

Random ran=new  random（）；   初始化的意思

例如  for (; ; )

            {

                string a = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";

                Random ran = new Random();

                string a1 = "";

                for (int i = 1; i <= 4; i++)

                {

                    int b = ran.Next(a.Length);//索引值

                    string b1 = a.Substring(b, 1);

                    a1 = a1 + b1;

                }

                Console.WriteLine(a1);

                Console.Write("请输入验证码");

                string s = Console.ReadLine();

                a1 = a1.ToLower();

                s = s.ToLower();

                if (s == a1)

                {

                    Console.WriteLine("验证码正确，请继续");

                    break;

                }

                else

                {

                    Console.Clear();

                    Console.WriteLine("验证码错误");

 

                }

 

            }

            Console.ReadLine();

数组

数组就是相同数据类型的元素按一定顺序排列的集合

数组中元素的索引是从0开始

一维数组

第一种定义方式int[]变量名=new  int[n]  n代表放几个值

第二种定义方式int[]变量名=new  int[]{1,2,3,4,5};

例如//Console.Write ("请输入班级的人数");

            //int a =int.Parse (Console.ReadLine ());

            //double []fen=new double [a];

            //double  he = 0;

            //for (int i = 0; i < a; i++)

            //{

            //    Console.WriteLine ("第"+(i+1)+"个人分数是");

            //    fen[i]=double .Parse (Console.ReadLine ());

 

            //he += fen[i];

            //}

            //Console.WriteLine("班级的平均分是"+he/a);

二维数组

第一种定义方式int[,]变量名=new  int[几个数组,一个数组中有几个数];

第二种定义方式int[,]变量名=new  int[4,2]{{1,2}{3,4}{5,6}{7,8}};

例如

//输入班级的人数，将每一个人的

 

            //语文，数学，英语成绩输入

 

            //Console.Write("请输入班级的人数");

            //int a = int.Parse(Console.ReadLine ());

            //double[,] fen = new double[a, 3];

            //for (int i = 0; i < a; i++)

            //{

            //    for (int c = 0; c < 3; c++)

            //    {

            //        if (c == 0)

            //        {

            //            Console.WriteLine("第"+(i+1)+"个人的语文分数是：");

            //        }

            //        if (c == 1)

            //        {

            //            Console.WriteLine("第" + (i + 1) + "个人的语文分数是：");

            //        }

            //        if (c == 2)

            //        {

            //            Console.WriteLine("第" + (i + 1) + "个人的语文分数是：");

            //        }

            //    fen [i,c]=double .Parse (Console.ReadLine ());

            //    }

            //}

            //Console.ReadLine();

多维数组

第一种定义方式int[,,]变量名=new  int[2,4,2];

第二种int[,,]变量名=new  int[2,4,2]{{1,2}{3,4}{5,6}{7,8}}{{9,10}{11,12}{13,14}{15,16}};