C#学习之路，学习笔记 第五章 枚举、结构体和数组

5.1 枚举

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 枚举{    class Program    {        //5.1枚举        //C#支持枚举类型，简单地说就是把字符串映射到数字0、1、2...上的类型        //需要注意的是,枚举类型的定义代码要卸载主函数的外面，和主函数并列放置        enum WeekDays { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday };        static void Main(string[] args)        {            WeekDays today = WeekDays.Sunday;            if ((today == WeekDays.Saturday) || (today == WeekDays.Sunday))            {                Console.WriteLine("I love the weekends!");            }            else            {                Console.WriteLine("Back to work.");            }            //表面上7个枚举项都是字符串，实际上每个枚举项都关联了一个整数，            //所以我们可以直接用枚举项关联的整数进行赋值，但是必须进行显式转换（强制类型转换）            today = (WeekDays)3;            Console.WriteLine("Today is " + today);  //运行结果Today is Wednesday            //如果我们想输出该枚举项关联的整数，语句如下            today = WeekDays.Sunday;            Console.WriteLine((int)today);            //因为每个枚举项都关联一个整数，所以枚举型变量可以参与运算和循环            for(today = WeekDays.Sunday; today<=WeekDays.Saturday; today++)            {                Console.WriteLine(today);            }            //在默认情况下枚举项的关联值一次对应0、1、2、3...。            //必要时我们可以通过赋值的方法改变枚举项所关联的整数值            /*                enum WeekDays                {                    Sunday = 5;                    Monday,                    Tuesday,                    Wednesday,                    Thursday = 100;                    Friday;                    Saturday;                }                Console.WriteLine("   Sunday:  {0}", (int)WeekDays.Sunday);                Console.WriteLine("   Monday:  {0}", (int)WeekDays.Monday);                Console.WriteLine("  Tuesday:  {0}", (int)WeekDays.Tuesday);                Console.WriteLine("Wednesday:  {0}", (int)WeekDays.Wednesday);                Console.WriteLine(" Thursday:  {0}", (int)WeekDays.Thursday);                Console.WriteLine("   Friday:  {0}", (int)WeekDays.Friday);                Console.WriteLine(" Saturday:  {0}", (int)WeekDays.Saturday);            */            //运行结果如下            /*                   Sunday:  5                   Monday:  6                     Tuesday:  7                Wednesday:  8                 Thursday:  100                   Friday:  101                 Saturday:  102            */            //在默认情况下，枚举项关联值的类型为int型，如果需要，            //我们可以为枚举项指定更合适的数据类型。关联值可以为byte、            //sbyte、short、ushort、int、uint、long、ulong等类型。            /*                enum WeekDays: short                {                    Sunday,                    Monday,                    Tuesday,                    Wednesday,                    Thursday,                    Friday,                    Saturday                }            */        }    }}

运行结构如下：

5.2 结构体

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 结构体{    //和枚举类型一样，结构体的定义代码应在主函数之外。其实所有定义类型的代码都应在主函数之外    //定义结构体    struct Student    {        public int number;        public string name;        public string sex;        public string birthday;    }    class Program    {        static void Main(string[] args)        {            //声明变量hfy并为其成员变量赋值            Student hfy;            hfy.number = 2000069001;            hfy.name = "寒飞雨";            hfy.sex = "男";            hfy.birthday = "1980.11.06";            //声明变量honey并为其成员变量赋值            Student honey;            honey.number = 2000070040;            honey.name = "Britney jean Spears";            honey.sex = "女";            honey.birthday = "1981.12.02";            //输出honey的信息            Console.WriteLine("学号：" + hfy.number);            Console.WriteLine("姓名：" + hfy.name);            Console.WriteLine("性别：" + hfy.sex);            Console.WriteLine("生日：" + hfy.birthday);            //输出honey的信息            Console.WriteLine("学号：" + honey.number);            Console.WriteLine("姓名：" + honey.name);            Console.WriteLine("性别：" + honey.sex);            Console.WriteLine("生日：" + honey.birthday);        }    }}

运行结构如下：

5.3 数组

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 数组{    class Program    {        static void Main(string[] args)        {            //声明数组            int[] scores = {120,149,112,133,127};            //用for语句处理数组            int sum = 0;            for(int i = 0;i<scores.Length;i++)            {                Console.WriteLine(scores[i]);  //输出5科成绩                sum = sum + scores[i];         //计算5科总分            }            float average = sum / (scores.Length); //计算5科平均成绩            Console.WriteLine("总  分：{0}",sum);            Console.WriteLine("平均值：{0}", average);            string[] friendNames = new string[3];            friendNames[0] = "张三";            friendNames[1] = "李四";            friendNames[2] = "王五";            Console.WriteLine("我共有{0}位朋友：",friendNames.Length);            for(int i=0; i<friendNames.Length; ++i)            {                Console.WriteLine(friendNames[i]);            }            //forreach循环语句            string[] friends = {"张三","李四","王五"};            Console.WriteLine("我共有{0}位朋友：", friends.Length);            foreach (string mingzi in friends)            {                Console.WriteLine(mingzi);            }            //二位数组            //声明二维数组            int[,] Matrix = { {1,2,3},{4,5,6},{7,8,9} };            //双重for语句遍历            for(int i = 0; i<3; ++i)            {                for(int j = 0; j<3; ++j)                {                    Console.Write(Matrix[i,j] + " ");                    sum += Matrix[i,j];                }                Console.WriteLine("\n");  //每输出三个数字换行            }            //不等长二维数组            int[][] jaggedArray = new int[2][];            jaggedArray[0] = new int[3] { 1, 2, 3 };            jaggedArray[1] = new int[4] { 1, 2, 3 ,4};        }    }}

运行结果如下：