函数(邮箱、验证码、体重、阶乘、累加)

namespace ConsoleApplication91024hanshu

 {

     class hanshua

     {         //private只在当前class使用,需要初始化再使用!

         //public公共的,可以在整个命名空间namespace使用,使用时 要初始化!

         //static 的访问范围静态的,不能跨类即class!使用时不用初始化!

               public void Hanshu(int i,int j,string s )

         {

             Console.WriteLine(i);

             Console.WriteLine(j);

             Console.WriteLine(s);

             Console.WriteLine("这是第一个 函数操作。");

         }

         /// <summary>

         /// 输入参数n,正整数,可以求出n的累加和!        //   可以注解函数

         /// </summary>

         /// <param name="n"></param>

         public void qiuhe(int n)

        {

             int sum=0;

             for (int a=0;a<=n;a++)

             {             sum+=a;             }

             Console.WriteLine ("累加求和结果"+sum);

         }

        public string fanhuizhi()

         {

            string s = "nihao ";

             return s;        // return"nihao";    //  直接赋值   ,返回值都是用return接收!

         }

         public int jiecheng(int m)         //阶乘!

         {

            int a = 1;

            for (  int b = 1; b <= m; b++)

             {                 a *= b;             }

             return a;

        }

         public void outzhi(int i, out int j,out string x,out double k)    //可以返回多个值!

         {             j = i+1;             x = "hhh";             k = 1.3;          }

        public void tuzi (int i,out int j)

         {

            int a=i/2;

             int c=1;                   //c代表兔子数

             for (int b=1;b<=a;b++)     //b代表2个月的个数

             {             c*=2;             }

             j=c;

          }

        /*  static void yang(int i, out int j)

           {

               int cun = i; int zongshu = 0;

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

               {       

                     if(i==7)

                 { zongshu=2;}

                  else

                 { zongshu =(2*(zongshu+1));}

               }

              j=zogshu ;

           }*/

         public int dgqiuyang(int cun)

         {

            int sum = 0;

             if (cun == 7)

            { return 2; }           //return返回,不是sum=2赋值!

             sum=2*(dgqiuyang(cun+1)+1);

                  //  在递归运算里return表示终结此函数,进而自动逆向运算,得出值!

               return sum;

        }

         static void Main(string[] args)

         {

           hanshua hs = new hanshua();    //hanshua代表类class,public函数引用须 初始化 它所在的class,

           hs.Hanshu(3,5,"hello");

            hs.qiuhe(10);//    此时表示n=10;

              //如果qiuhe是 static 函数,就可以直接使用!写成:qiuhe(10);

            string s= hs.fanhuizhi();

           int b= hs.jiecheng(5);

           int j = 0;    //要创建变量j,否则没法输出!

           string x = "";

           double k = 0; 

        //  hs.outzhi(3, out j, out x, out k);//顺序要按照函数里的顺序写!

          hs.tuzi(0, out j);

           Console.Write(b+" "+j);

            Console.ReadLine();

//////////////////////应用

namespace ConsoleApplication91026huigu

 {

     class Program

     {

         static void dayin01()

         {         Console.WriteLine("01,hello");         }

   #region 解二次方程                 //要单独一行才起作用 

        /// <summary>

         ///

         /// </summary>

         /// <param name="a"></param>

         /// <param name="b"></param>

         /// <param name="c"></param>

         /// <param name="geng1"></param>

         /// <param name="geng2"></param>

         /// <returns></returns>

       public string jiefangcheng02(double a, double b, double c, out double geng1,out double geng2)

         {              /**///          求解a*x*x+bx+c=0             //b*b-4ac

            geng2 = 0; geng1 = 0;

                 if (a == 0)

                    { return "此时不是一元二次方程"; }

                 else if (b * b < 4 * a * c)

                     { return"无解"; }

                 else if (b * b == 4 * a * c)

                    { geng2=geng1= -b / (2 * a);    //可以连等,也可以分开写。

                return "两个相同实根";         //return 只能接收一个量!

                         }

                else

                    {

                       geng1 = (-b + Math.Sqrt(b * b - 4 * a * c))/2*a;

                     geng2=(-b - Math.Sqrt(b * b - 4 * a * c))/2*a ;

                     return "两个不同实根";

                     }

           }

    #endregion

    #region 判断身高体重是不是标准

         /// <summary>

         ///

        /// </summary>

         /// <param name="sex"></param>

         /// <param name="weight"></param>

         /// <param name="high"></param>

         /// <returns></returns>

        public string tizhong(string sex, double weight, double high)

        {

           if (sex=="男" )

            {

               double bzweight = high - 100;

                 double cha = weight - bzweight;        //此处要分清e.f大小值然后判断

                                if (cha > 3)

                 {     //Console.Write("不好意思,你有点胖了,该减肥了!");       return "超标";                 }                               else if (cha < -3)

                 {    // Console.Write("不好意思,你需要补充营养!");         return "偏瘦";                 }

                               else

                {      // Console.Write("您的身材很标准,继续保持!");           return "标准";                 }

            }

             else if (sex == "女")

             {

                 double bzweight = high - 110;

                 double cha = weight - bzweight;

                 if (cha > 3)

                 { //Console.Write("不好意思,你有点胖了,该减肥了!");

                       return "超标";                 }

                  else if (cha < -3)

                 {        // Console.Write("不好意思,你需要补充营养!");

                         return "偏瘦";                 } 

                  else

                {         // Console.Write("您的身材很标准,继续保持!");

                       return "标准";                 }

             }

             else

             {     //Console.WriteLine("不知道哪错了,可能是你还没有长大!");       return "错误";             }

         }

 #endregion

        #region==生成四位验证码的方法==

        /// <summary>

        ///随机生成4位验证码,并输入比对是否输入正确

        /// </summary>

        /// <returns></returns>

        public string yanzhengma()

        {

            string s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_";

            Random r = new Random();

            int zi1 = r.Next(63);

            int zi2 = r.Next(63);

            int zi3 = r.Next(63);

            int zi4 = r.Next(63);

            string a = s.Substring(zi1, 1);

            string b = s.Substring(zi2, 1);

            string c = s.Substring(zi3, 1);

            string d = s.Substring(zi4, 1);

            string suiji = a + b + c + d;

            //Console.WriteLine(suiji);

            return suiji;

        }

#endregion

#region==判断邮箱是否正确==

        /// <summary>

        ///判断邮箱格式是否输入正确

        /// </summary>

        /// <param name="email"></param>

        /// <returns></returns>

        public bool youxiang(string semail)

        {

            string bidui = "abcdefghijklmnopqrstuvwxyz1234567890_.@";

            int sant = 0;

            int sdian = 0;

            int zhengque = 0;

            for (int i = 0; i < semail.Length; i++)

            {

                string sc = semail.Substring(i, 1);

                bool b = bidui.Contains(sc);

                if (b)

                {

                    if (sc == "@")

                    {                         sant++;                     }

                    if (sc == ".")

                    {                         sdian++;                     }

                }

                else

                {                    // Console.WriteLine("您的邮箱有特殊字符,请检查输入!");

                    return false;

                    zhengque++;

                }

            }

            if (sant == 1 && sdian == 1 && zhengque == 0)

            {

                if (semail.Contains("@.") || semail.IndexOf("@") > semail.IndexOf("."))

                {

                   // Console.WriteLine("@和.之间需要有邮箱地址代表字符,并且@必须在.前面");

                    return false;

                }

                else

                {

                    if (semail.EndsWith(".com") || semail.EndsWith(".cn"))

                    {                         //Console.WriteLine("输入正确");

                        return true;

                    }

                    else

                    {

                      //  Console.WriteLine("邮箱必须以.com或者.cn结尾");

                        return false;

                    }

                }

            }

            else

            {                 //Console.WriteLine("注意邮箱中只能出现一个@和一个.");

                return false;

            }

        }

         #endregion

            static void Main(string[] args)

             {

               /*                  dayin();               //直接引用函数!

                 Console.ReadLine();//此时 可以打印     01,hello     */

//解一元二次方程!

           /* Console.Write("输入a:");

               double a = double.Parse(Console.ReadLine());

             Console.Write("输入b:");

            double b = double.Parse(Console.ReadLine());

            Console.Write("输入c:");

            double c = double.Parse(Console.ReadLine());

             double gen1; double geng;       //要创建相应类型的变量接收,可以不是创建函数中的变量名!

             Program qiujie = new Program();

            qiujie.jiefangcheng02(a, b, c, out gen1, out geng);

            Console.WriteLine("    02,  1  :"+gen1+"    2   :"+geng);

             Console.ReadLine();   */

          /*                   //判断是不是标准体重 

          Console.WriteLine("sex:");

         string a=Console.ReadLine ();

         Console.WriteLine("high:");

         double b=Convert.ToDouble( Console.ReadLine ());

         Console.WriteLine("weight:");

         double c=double.Parse (Console.ReadLine ());

//下面引用函数 ,前面是在获取函数所需要的必要参数!

          Program shengao=new Program ();

          string d   =   shengao .tizhong(a,b,c);

           Console.WriteLine(d);

          Console.ReadLine();   */

   //这是验证码调用部分
     /*       Program pg = new Program();
            string suiji = pg.yanzhengma();
            Console.WriteLine(suiji);
            while (true)
            {
                string shuru = Console.ReadLine();
                shuru = shuru.ToUpper();
                suiji = suiji.ToUpper();
                if (shuru == suiji)
                {
                    Console.Write("输入正确");
                    break;
                }
                else
                {
                    Console.Write("重新输入");
                    Console.Clear();                   //清空 控制台界面 的程序代码!
                    suiji = pg.yanzhengma();
                    Console.WriteLine(suiji);
                }
            }

             Console.ReadLine();             */

  //邮箱函数调用部分,判断邮箱格式 对错!
            Console.WriteLine("请输入你的邮箱:");
            string semail = Console.ReadLine();
            semail = semail.ToLower();
            Program pg = new Program();
            bool b = pg.youxiang(semail);
            Console.WriteLine(b);
            Console.ReadLine();

原文地址:https://www.cnblogs.com/huaze/p/4053393.html