static void test06()
        {
            for (int i = 0; i < 20; i++)
            {
                Console.Write("* ");
            }
        }
        static void test07()
        {
            int sum = 0;
            for (int i = 1; i < 101; i++)
            {
                sum += i;
                Console.WriteLine(sum);
            }
            Console.WriteLine(sum);
        }
        static void test08()
        {
            for (int i = 1 ; i < 101; i++)
            {
                if (i%2==0)
                {
                    Console.WriteLine(i);
                }
            }
        }
        static void test09()
        {
            Console.WriteLine("请输入整数n：");
            int n = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("请输入整数m：");
            int m = Convert.ToInt32(Console.ReadLine());
            int sum1 = 0;
            int sum2 = 0;
            if (m > n)
            {

                for (int i = n; i <= m; i++)
                {
                    if (i % 7 == 0)
                    {
                        Console.WriteLine(i);
                        sum1 += i;
                    }
                }
                Console.WriteLine("所有能被7整除的数的和是：" + sum1);
            }
            else if (m < n)
            {
                for (int i = m; i <= n; i++)
                {
                    if (i % 7 == 0)
                    {
                        Console.WriteLine(i);
                        sum2 += i;
                       
                    }
                }
                Console.WriteLine("所有能被7整除的数的和是：" + sum2);
            }
            
            else
            {
                if (m%7==0)
                {
                    Console.WriteLine(m);
                    Console.WriteLine("所有能被7整除的数的和是：" + m);
                }                             
            }                     
        }
        static void test10()
        {
            Console.WriteLine("请输入整数n：");
            int n = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("请输入整数m：");
            int m = Convert.ToInt32(Console.ReadLine());
            string odd="";
            string even="";
            if (m > n)
            {
                for (int i = n; i <= m; i++)
                {
                    if (i % 2 == 0)
                    {
                        odd += i+" ";
                    }                   
                    else
                    {
                        even += i+" ";
                    }
                }
                Console.WriteLine(odd);
                Console.WriteLine(even);
                
            }
            else if (m < n)
            {
                for (int i = m; i <= n; i++)
                {
                    if (i % 2 == 0)
                    {
                        odd += i + " ";
                    }
                    else
                    {
                        even += i + " ";
                    }
                }
                Console.WriteLine(odd);
                Console.WriteLine(even);
            }

            else
            {
                if (m % 2 == 0)
                {
                    Console.WriteLine(m);
                }
                else
                {
                    Console.WriteLine(m);
                }
            }
        }

static void test02()
        {
            int student = 80000;
            int year = 2006;
            while (student<200000)
            {
                student =(int )(student* 1.25);
                year++;
                Console.WriteLine("student="+student);
            }
            Console.WriteLine("year="+year);           
        }
        static void test03()
        {
            Console.WriteLine("请输入学生个数：");
            int student = Convert.ToInt32(Console.ReadLine());
            double sum = 0;
            for (int i = 1; i <= student; i++)
            {
                Console.WriteLine("请输入{0}号学生的年龄：", i);
                double old = Convert.ToInt32(Console.ReadLine());
                sum += old;
            }
            double averageValue=sum/student;
            Console.WriteLine("平均年龄是：{0}",averageValue);
        }
        static void test04()
        {
            Console.WriteLine("请输入整数n：");
            int n = Convert.ToInt32(Console.ReadLine());
            for (int i = 1; i <=n; i++)
            {
                Console.Write(" "+i);
            }
        }

static void test01()
        {
            Console.WriteLine("请输入整数n：");
            int n = Convert.ToInt32(Console.ReadLine());
            for (int i = 0; i >=0; i++)
            {
                if (n>1)
                {
                    break;
                }
                else
                {
                    Console.WriteLine("输入有误，请重新输入：");
                    n = Convert.ToInt32(Console.ReadLine());
                }
            }
            int j = 0;
            while (n>1)
            {
                if (n % 2 != 0)
                {
                    n = 3 * n + 1;
                }
                else if (n % 2 == 0)
                {
                    n /= 2;
                }
                
                j++;
                Console.WriteLine("每次变换后n=" + n);               
            }
            Console.WriteLine("变换次数j是：" + j);
        }

        static void test11()
        {
            Console.WriteLine("请输入整数n1：");
            int n1 = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("请输入整数n2：");
            int n2 = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("你输入的n1是：{0},你输入的n2是：{1}",n1,n2);
            int i = n1;
            if (n2>n1)
            {
                while (i<=n2)
                {
                    if (i%2==0)
                    {
                        Console.WriteLine(i);
                    }                   
                    i++;
                }
            }
            else
            {
                while (i >= n2 )
                {
                    if (i % 2 == 0)
                    {
                        Console.WriteLine(i);
                    }
                    i--;
                }
            }         
        }

else if是连用的、

swtich(number){

case 1:做什么事numeber=1的时候

break;

case2 :

break;

case3:

break;

default:上诉情况都不是可有可无

break;

}

double res=（3+8）/2；

这只能出整数，因为后面的数字不是小数型；

 static void test11()
        {
            Console.WriteLine("请输入三个整数");
            int num1 = Convert.ToInt32(Console.ReadLine());
            int num2 = Convert.ToInt32(Console.ReadLine());
            int num3 = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("你输入的三个整数是{0},{1},{2}",num1,num2,num3);
            if (num1>num2)
            {
                if (num2>num3)
                {
                    Console.WriteLine("三个整数从小到大排序是：{0},{1},{2}", num3, num2, num1);
                }
                else if(num2<num3)
                {
                    if (num1>num3)
                    {
                        Console.WriteLine("三个整数从小到大排序是：{0},{1},{2}", num2, num3, num1);
                    }
                    else if (num1<num3)
                    {
                        Console.WriteLine("三个整数从小到大排序是：{0},{1},{2}", num2, num1, num3);
                    }
                }               
            }
            else if (num1<num2)
            {
                if(num1>num3)
                {
                    Console.WriteLine("三个整数从小到大排序是：{0},{1},{2}", num3, num1, num2);
                }
                else if (num1<num3)
                {
                    if (num3>num2)
                    {
                        Console.WriteLine("三个整数从小到大排序是：{0},{1},{2}", num1, num2, num3);
                    }
                    else if (num3<num2)
                    {
                        Console.WriteLine("三个整数从小到大排序是：{0},{1},{2}", num1, num3, num2);
                    }                  
                }
            }
           
        }

静态的  返回值 方法名 参数

方法的定义（在Main方法之外，上边或者下边）

static   void    Main (string[] args)

static void VerifyUsername()

{

方法体

}

方法体的调用：

定义的方法名（）；

VerifyUsername(); 

String name ="aaaa,bbbb,ccccc,dddd";

//name.Spilt(' ')分割后得到字符串数组

string[] strArray = name.Split(',');

foreach(string str in strArray)

{

     Console.WriteLine(str);

}

string str =Console.ReadLine();

string[] strArray = str.Split(" ");

int[] intArray = new int[strArray.Length];

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

{

int number=Convert.ToInt32(strArray[i]);

intArray[i]=number;

}

获得一组数字

将字符串转换为可编辑数组方法：

//string aa = ("abcdefghijklmnopqrstuvwxyz");

string str=Console.ReadLine();

//将接收到的字符串，转换为字符数组（可编辑替换）
char[] strArray = str.ToCharArray();

//遍历所有字符

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

{

      if((strArray[i]>='a' && strArray[i]<='z')||

      ( strArray[i]>='A' && strArray[i]<='Z'))

     if(strArray[i]>'z'&&strArray[i]<'z'+4)

     {

           strArray[i]=(char)strArray[i]-26//处理xyz  

     }

 if(strArray[i]>'Z'&&strArray[i]<'Z'+4)

     {

           strArray[i]=(char)strArray[i]-26//处理XYZ  

     }

     {

  //给所有字符加密

      strArray[i]=(char)strArray[i]+3

      }

  //遍历所有字符并输出

      foreach(char temp in strArray)

      {

       Console.Write(temp);

      }

using System;

namespace _0015_if_elseif语句_多条件判断
{
    internal class Program
    {
        static void Main(string[] args)
        {

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


            ////if if else 满足某一个执行某一个;
            //if (score > 100)
            //{
            //    Console.WriteLine("最高分为100哦");
            //}

            //if (score >= 90 && score <= 100)
            //{
            //    Console.WriteLine("A");
            //}

            //if (score <= 89 && score >= 80)
            //{
            //    Console.WriteLine("B");
            //}

            //if (score <= 79 && score >= 60)
            //{
            //    Console.WriteLine("C");
            //}

            //if (score < 60)
            //{
            //    Console.WriteLine("D");
            //}

            //if () {} else if () {} else () {}
            if (score >= 100)
            {
                Console.WriteLine("S");
            }
            else if (score >= 90)
            {
                Console.WriteLine("A");
            }
            else if (score >= 80)
            {
                Console.WriteLine("B");
            }
            else if (score >=60)
            {
                Console.WriteLine("C");
            }else if (score < 60)
            {
                Console.WriteLine("D");
            }
        }
    }
}

foreach:遍历数组命令 只能正序遍历

foreach(int temp in a)

{

Console.Write(a[i] + " ");

}

老办法：

for(int i=1;i<a.Length;i++) //获取数组个数

{

  Console.Write(a[i] + " ");

}

数组的赋值：

1：int[] a={1,2,3,4,5};

2: a=new int [x];

3:a=newint [6]{1,2,3,4,5,6};

Console WriteLine("  ")

Random rd=new Random();

Console.WriteLine(rd.Next(1,10));

int number=rd.Next(1,101);

using System;

namespace _0014_if语句嵌套
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Console.WriteLine("奇数与偶数");
            //int number = Convert.ToInt32(Console.ReadLine());

            //if (number % 2 == 1)
            //{
            //    Console.WriteLine("奇数");
            //}
            //else
            //{
            //    Console.WriteLine("偶数");
            //}

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

            //if (age >= 18 && age <= 30 && age %2 == 1)
            //{
            //    Console.WriteLine("获得奖品");
            //}
            //else
            //{
            //    Console.WriteLine("好可惜啊,你没有奖品(手动狗头)");
            //}
            Console.WriteLine("看看你有没有获得奖品");
            Console.ReadKey();
            if (age >= 18 && age <= 30)
            {
                Console.WriteLine("你可以参加活动");
                Console.ReadKey();
                if (age % 2 == 1)
                {
                    Console.WriteLine(@"你获得奖品
                                        作业大礼包(狗头)
");
                }
                else
                {
                    Console.WriteLine("你没有获得奖品");
                }
            }
            else
            {
                Console.WriteLine("你不可以参加活动");
            }
        }
    }
}

一组数代码

string str = Console.ReadLine();
            string[] strArray = str.Split(" ");  //输入一个字符串并用空格隔开
            int[] intArray = new int[strArray.Length];
            for (int i = 0; i < strArray.Length; i++)
            {
                int number = Convert.ToInt32(strArray[i]);
                intArray[i] = number;
            }

求一个数字字符代表的数字：int number=a-'0';

C