函数

using System;
using System.Collections.Generic;
using System.Text;

namespace 函数练习
{
    class Program
    {
        /// <summary>
        /// 输入一个数，求和函数
        /// </summary>
        /// <param name="n"></param>
        /// <returns></returns>
        public int qiuhe(int n)
        {
            int sum = 0;
            for (int i = 0; i <=n; i++)
            {
                sum += i;
            }
            return sum;
        }
        /// <summary>
        /// 几千几百减几百不退位，无返回值，无参数
        /// </summary>
        public void butuiwei()
        {
            Random r = new Random();
            int c, d, e, f;
            int a = r.Next(1, 10);
            int b = r.Next(1, 10);
            f = r.Next(1, b);
            d = a * 1000 + b * 100;
            e = f * 100;
            if (b >= f)
            {
                c = d - e;
                Console.WriteLine(d + "-" + e + "=" + c);
            }
            else
            {
                Console.WriteLine("错误");
            }
        }
        /// <summary>
        /// 判断闰年，返回结果
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public string runnian(string s)
        {
            string s1 = "";  
            string s2;
            try
            {
                DateTime rn1 = Convert.ToDateTime(s + "-2-29");
                s1 = "年是闰年";
            }
            catch (Exception)
            {
                s1 = "年不是闰年";

            }
            finally
            {
                s2 = s + s1;
            }
            return s2;
        }
        /// <summary>
        /// 给出单词，打印单词的各个字母
        /// </summary>
        /// <param name="s"></param>
        public void danci(string s)
        {
            int a = s.Length;
            for (int i = 0; i < a; i++)
            {
                Console.WriteLine(s.Substring(i, 1));
            }
        }
        /// <summary>
        /// 冒泡排序，由大到小
        /// </summary>
        /// <param name="a">int 数组a</param>
        public int[] paixu(int[] a)
        {
            for (int i = 0; i < a.Length; i++)
            {
                for (int j = i; j < a.Length - 1; j++)
                {
                    if (a[i] < a[j + 1])
                    {
                        int b;
                        b = a[i];
                        a[i] = a[j + 1];
                        a[j + 1] = b;
                    }
                }
            }
            return a;
        }
        /// <summary>
        /// 数组求和
        /// </summary>
        /// <param name="a"></param>
        /// <returns></returns>
        public int shuzuqiuhe(int[] a)
        {
            int x = 0;
            for (int i = 0; i < a.Length; i++)
            {
                x = a[i] + x;

            }
            return x;
        }
        public 
        static void Main(string[] args)
        {
            while (true)
            {
                double x;
                int[] a = new int[10];
                for (int i = 0; i < 10; i++)
                {
                    Console.WriteLine("第" + (i + 1) + "位同学给班长打分：");
                    a[i] = Convert.ToInt32(Console.ReadLine());
                }
                new Program().paixu(a);
                x = new Program().shuzuqiuhe(a);
                Console.WriteLine("去掉一个最高分" + a[0] + "分\t" + "去掉一个最低分" + a[9] + "分");
                Console.WriteLine("总分是" + x);
                Console.WriteLine("平均分" + (x / (a.Length - 2)));
                Console.ReadLine();   
            }
            
        }
    }
}