20141211--C# 构造函数

namespace fengzhuang
{
    class Class2
    {
        private string _Name;
        private string _Code;
        public string _Sex;

        public Class2()//构造函数
        {
            _Sex = "男";//每次初始化都会默认_Sex的值为“男”
            Console.WriteLine("构造函数");
        }
        public string nv()//函数 
        {
            _Sex = "女";
            return _Sex;
        }
    }
}

static void Main(string[] args)
        {
            Class2 op=new Class2();//本身就存在的，只要初始化一下类，便会调用函数，
            Console.WriteLine(op._Sex);
            op.nv();//调用函数，
            Console.WriteLine(op._Sex);
            Console.WriteLine();
            Console.ReadLine();
        }

习题：

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

namespace xueshengxuanke
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("请输入学生人数：");
            int n = int.Parse(Console.ReadLine());
            Console.WriteLine("请输入学生学号、姓名、分数");
            ArrayList arr = new ArrayList();
            for (int i = 0; i < n; i++)
            {
                student s = new student();
                Console.Write("学号：");
                s.Code = int.Parse(Console.ReadLine());
                Console.Write("姓名：");
                s.Name = Console.ReadLine();
                Console.Write("分数：");
                s.Score = decimal.Parse(Console.ReadLine());

                arr.Add(s);
            }

            decimal sum = 0;

            for (int i = 0; i < n; i++)
            {
                student avgs = (student)arr[i];
                sum += avgs.Score;
            }

            ArrayList newarr = new student().Maopao(arr);

            student ss1 = (student)newarr[0];
            Console.WriteLine("姓名：{0}最高分为：{1}", ss1.Name, ss1.Score);
            int x = n - 1;
            student ss2 = (student)newarr[x];
            Console.WriteLine("姓名：{0}最低分为：{1}", ss2.Name, ss2.Score);
            Console.WriteLine("平均分：{0}", sum / n);


            for (int i = 0; i < n; i++)
            {
                student avgs = (student)newarr[i];
                Console.WriteLine("学生名次为：***********************************");
                Console.WriteLine("学号         姓名           分数                 名次");
                Console.WriteLine("{0}         {1}           {2}                 {3}", avgs.Code, avgs.Name, avgs.Score, i + 1);
            }


            Console.ReadLine();
        }
    }
}

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

namespace xueshengxuanke
{
    class student
    {
        private int _Code;

        public int Code
        {
            get { return _Code; }
            set { _Code = value; }
        }
        private string _Name;

        public string Name
        {
            get { return _Name; }
            set { _Name = value; }
        }
        private decimal _Score;

        public decimal Score
        {
            get { return _Score; }
            set { _Score = value; }
        }

        /// <summary>
        /// 接收arraylist，排序后，返回arraylist
        /// </summary>
        /// <param name="arr">存放了student类对象的arraylist</param>
        /// <returns>返回排序后的集合</returns>
        public ArrayList Maopao(ArrayList arr)
        {
            int n = arr.Count;
            for (int i = 0; i < n; i++)
            {
                for (int j = i; j < n; j++)
                {
                    student s1 = (student)arr[i];
                    student s2 = (student)arr[j];
                    if (s1.Score < s2.Score)
                    {
                        student zhong = new student();
                        zhong = s1;
                        arr[i] = s2;
                        arr[j] = zhong;
                    }
                }
            }

            return arr;
        }
    }
}