C#方法（函数）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _04.方法_函数_
{
    class Program
    {
        static void Main(string[] args)
        {
            //求2个整数的最大值
            //int max = Program.GetMax(1, 2);
            //Console.WriteLine("最大值为{0}", max);
            //Console.ReadKey();

            //判断闰年
            //bool b = IsRun(2100);
            //Console.WriteLine(b);
            //Console.ReadKey();

            //输入数字跳出循环，否则继续
            //Console.WriteLine("请输入一个数字");
            //string input = Console.ReadLine();
            //int number = GetNum(input);
            //Console.WriteLine(number);
            //Console.ReadKey();

            //输入yes
o，否则继续
            //Console.WriteLine("请输入yes
o");
            //string input = Console.ReadLine();
            //string result = IsYesOrNo(input);
            //Console.WriteLine(result);
            //Console.ReadKey();

            //求数组的和
            //int[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
            //int result = GetSum(nums);
            //Console.WriteLine(result);
            //Console.ReadKey();

            //求数组的最大、最小、总和、平均值
            //int[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
            //int max = 0;
            //int min = 0;
            //int sum = 0;
            //int avg = 0;
            //Test(nums,out max,out min,out sum,out avg);
            //Console.WriteLine(max);
            //Console.WriteLine(min);
            //Console.WriteLine(sum);
            //Console.WriteLine(avg);
            //Console.ReadKey();

            //判断登录条件
            //Console.WriteLine("username");
            //string username = Console.ReadLine();
            //Console.WriteLine("password");
            //string password = Console.ReadLine();
            //string msg;
            //bool b = IsLogin(username, password, out msg);
            //Console.WriteLine(b);
            //Console.WriteLine(msg);
            //Console.ReadKey();

            //交换2个int型的整数
            //int n1 = 10;
            //int n2 = 20;
            //Change(ref n1, ref n2);
            //Console.WriteLine("{0}, {1}", n1, n2);
            //Console.ReadKey();

            //输入姓名、学号、成绩，计算总成绩
            ////int[] s = { 99, 99, 99 };
            //Score("张三", 101, 99, 99, 99);
            //Console.ReadKey();

            //方法递归
            //TellStory();
            //Console.ReadKey();

            //方法综合练习6.7.12

            //求一个字符串数组中最长的元素
            //string[] names = { "马云", "罗振宇", "科比布莱恩特", "扎克伯格"};
            //Console.WriteLine(GetLongStr(names));
            //Console.ReadKey();
        }

        #region 2个数的最大值
        /// <summary>
        /// 求2个数的最大值
        /// </summary>
        /// <param name="n1">第一个整数</param>
        /// <param name="n2">第二个整数</param>
        /// <returns>返回最大值</returns>
        public static int GetMax(int n1, int n2)
        {
            return n1 > n2 ? n1 : n2;
        }
        #endregion

        #region 判断闰年
        /// <summary>
        /// 判断给出的年份是否为闰年
        /// </summary>
        /// <param name="year">年份</param>
        /// <returns>bool</returns>
        public static bool IsRun(int year)
        {
            bool b = (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
            return b;
        }
        #endregion

        #region 判断用户的输入是否为数字
        /// <summary>
        /// 判断用户的输入是否为数字
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static int GetNum(string s)
        {
            while (true)
            {
                try
                {
                    int number = Convert.ToInt32(s);
                    return number;
                }
                catch
                {
                    Console.WriteLine("输入有误");
                    s = Console.ReadLine();
                }
            }
        }
        #endregion

        #region yes
o跳出循环
        /// <summary>
        /// 输入yes
o
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string IsYesOrNo(string input)
        {
            while (true)
            {
                if (input == "yes" || input == "no")
                {
                    return input;
                }
                else
                {
                    Console.WriteLine("请重新输入");
                    input = Console.ReadLine();
                }
            }
        }
        #endregion

        #region 求数组的和
        /// <summary>
        /// 求数组的和
        /// </summary>
        /// <param name="numbers"></param>
        /// <returns></returns>
        public static int GetSum(int[] numbers)
        {
            int sum = 0;
            for (int i = 0; i < numbers.Length; i++)
            {
                sum += numbers[i];
            }
            return sum;
        }
        #endregion

        #region 返回数组的最大、最小、总和、平均值
        /// <summary>
        /// 返回数组的最大、最小、总和、平均值
        /// </summary>
        /// <param name="nums">数组</param>
        /// <param name="max">多于反悔的最大值</param>
        /// <param name="min">多于反悔的最小值</param>
        /// <param name="sum">多于反悔的总和</param>
        /// <param name="avg">多于反悔的平均值</param>
        public static void Test(int[] nums, out int max, out int min, out int sum, out int avg)
        {
            max = nums[0];
            min = nums[0];
            sum = 0;
            for (int i = 0; i < nums.Length; i++)
            {
                if (nums[i] > max)
                {
                    max = nums[i];
                }
                if (nums[i] < min)
                {
                    min = nums[i];
                }
                sum += nums[i];
            }
            avg = sum / nums.Length;
        }
        #endregion

        #region 判断登录条件
        /// <summary>
        /// 判断登录条件
        /// </summary>
        /// <param name="uid">username</param>
        /// <param name="pwd">password</param>
        /// <param name="msg">错误信息</param>
        /// <returns></returns>
        public static bool IsLogin(string uid, string pwd, out string msg)
        {
            if (uid == "admin" && pwd == "123")
            {
                msg = "登录成功";
                return true;
            }
            else if (uid == "admin")
            {
                msg = "密码错误";
                return false;
            }
            else if (pwd == "123")
            {
                msg = "用户名错误";
                return false;
            }
            else
            {
                msg = "全部错误";
                return false;
            }
        }
        #endregion

        #region 交换2个int型的整数
        /// <summary>
        /// 交换2个int型的整数
        /// </summary>
        /// <param name="n1">n1</param>
        /// <param name="n2">n2</param>
        public static void Change(ref int n1, ref int n2)
        {
            int temp = n1;
            n1 = n2;
            n2 = temp;
        }
        #endregion

        #region 输入姓名、学号、成绩，计算总成绩
        /// <summary>
        /// 输入姓名、学号、成绩，计算总成绩
        /// </summary>
        /// <param name="name">姓名</param>
        /// <param name="id">学号</param>
        /// <param name="score">成绩数组</param>
        public static void Score(string name, int id, params int[] score)
        {
            int sum = 0;
            for (int i = 0; i < score.Length; i++)
            {
                sum += score[i];
            }
            Console.WriteLine("{0}的总成绩为{1}，学号{2}", name, sum, id);
        }
        #endregion

        #region 方法递归
        /// <summary>
        /// 方法递归
        /// </summary>
        public static int i = 0;
        public static void TellStory()
        {
            Console.WriteLine("从前有座庙");
            Console.WriteLine("庙里有个老和尚和小和尚");
            Console.WriteLine("有一天，老和尚对小和尚说：");
            i++;
            if (i > 10)
            {
                return;
            }
            TellStory();
        }
        #endregion

        #region 计算字符串数组中的最大值
        /// <summary>
        /// 计算字符串数组中的最大值
        /// </summary>
        /// <param name="s">数组</param>
        /// <returns>最大值</returns>
        public static string GetLongStr(string[] s)
        {
            string max = s[0];
            for (int i = 0; i < s.Length; i++)
            {
                if (s[i].Length > max.Length)
                {
                    max = s[i];
                }
            }
            return max;
        }
        #endregion
    }
}