C#学习之路

文章目录

• • • • c#组成、类型、实例化、枚举
      • 插箱与装箱、字节操作、字符串操作
      • 流程控值语句
      • 数据集合操作
      • 属性、方法、参数类型、重载
      • 结构和类

c#组成、类型、实例化、枚举

using System; //多个命名空间。与python的import功能形似 using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;namespace ConsoleApplication3 //建立命名空间 {class Program //类{//2.创建新类型class C {public int value = 0; //声明公共int类型变量value}//3.值类型 和引用类型public class stamp{public string name { get; set; } //string是引用类型，get和set代表可获取与可修改public int Age { get; set; }}//4.枚举类型enum MyDate {Sum=0,Mon=1,Tue=2,Web=3,Thu=4,Fri=5,Sat=6}static void Main(string[] args) //ain方法{Console.WriteLine("Hello word");//Console.ReadLine(); //等待任意输入继续//1.变量类型int ls = 927; //整形byte shj = 255; //字节类型Console.WriteLine("ls={0}", ls);Console.WriteLine("shj={0}", shj);float theMySUM = 9.27f;float theMuSums = 1.12F; //使用F或者f强制指定为浮点型double myDou = 927d;double mudou = 112D; //使用D或者d强制指定为浮点型//引用类型C r1 = new C();C r2 = r1;r2.value = 112;Console.WriteLine("Values:{0},{1}", r1.value,r2.value); //输出引用类型对象的value值//实例化stamp s1 = new stamp { name = "permist", Age = 25 };int age = s1.Age;string names = s1.name;Console.WriteLine("name:{0},age:{1}", s1.name,s1.Age); //输出引用类型对象的value值Console.WriteLine("name:{0},age:{1}", names,age); //输出引用类型对象的value值//枚举int k = (int)DateTime.Now.DayOfWeek; //代表星期几的返回值switch (k){case (int)MyDate.Sum:Console.WriteLine("今天是星期日");break;case (int)MyDate.Mon: Console.WriteLine("今天是星期一"); break;case (int)MyDate.Tue: Console.WriteLine("今天是星期二"); break;case (int)MyDate.Web: Console.WriteLine("今天是星期三"); break;case (int)MyDate.Thu: Console.WriteLine("今天是星期四"); break;case (int)MyDate.Fri: Console.WriteLine("今天是星期五"); break;case (int)MyDate.Sat: Console.WriteLine("今天是星期六"); break;}Console.ReadLine();}}}

插箱与装箱、字节操作、字符串操作

using System; //多个命名空间。与python的import功能形似 using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;namespace ConsoleApplication3 //建立命名空间 {class Program //类{static void Main(string[] args) {//类型转化，显式转换（强制转换）double x = 19810927.0112;int y = (int)x; //doble强转为intConsole.WriteLine(y);int y2=Convert.ToInt32(x);Console.WriteLine(y2);//拆箱与装箱//装箱将值类型转为引用类型过程//插箱是引用类型转为值类型//装箱实例如下int i = 2019;object obj = i;Console.WriteLine("1、i的值为{0} ;装箱的值对象为{1}", i, obj);i = 987;Console.WriteLine("2、i的值为{0} ;装箱的值对象为{1}", i, obj);//拆箱示例int j = 112;object obj2 = j;Console.WriteLine("1、j的值为{0} ;装箱的值对象为{1}", j, obj2);int h = (int)obj2;Console.WriteLine("2、j的值为{0} ;装箱的值对象为{1}", j, h);//特殊运算符//isint a1 = 0;bool result = a1 is int;Console.WriteLine(result);//?:string yesno= result ? "是int" : "不是int";Console.WriteLine("判断结果是:{0}", yesno);//new运算符，用户数组创建、对象创建、代表创建string[] phone = new string[5];phone[0] = "1";phone[1] = "2";phone[2] = "3";phone[3] = " ";phone[4] = "5";Console.WriteLine(phone[0]);Console.WriteLine(phone);//typeof运算符Type mytype = typeof(int); //获取int类型的原始类型Console.WriteLine("类型：{0}",mytype);//字符串类Sting的使用 Compare与CompaTo使用上区别不大string s1 = "你好" + "1";string s2 = "你好";if (String.Compare(s1, s2) == 0){Console.WriteLine("相等");}else {Console.WriteLine("不相等");}//equals方法1if (s1.Equals(s2)){Console.WriteLine("s1与s2相等");}else{Console.WriteLine("s1与s2不相等");}//equals方法2if (String.Equals(s1,s2)){Console.WriteLine("s1与s2相等");}else{Console.WriteLine("s1与s2不相等");}//Format格式化string news = String.Format("{0}{1}!!!!", s1, s2);Console.WriteLine(news);//截取字符串string s3 = s1.Substring(0, 2);Console.WriteLine(s3);//分割字符串string ss1 = "社会工业，团结发展";String[] splistrings = new String[100];splistrings=ss1.Split('，'); //返回的是字符串数组,分割字节分割。for (int q = 0; q < splistrings.Length; q++){Console.WriteLine("item{0}:{1}",q,splistrings[q]);}//插入字符和填充字符string ss2=ss1.Insert(0, "我说得，");string ss3=ss2.Insert(4, "，绝对");Console.WriteLine(ss3);//左右侧填充string ss4 = "xxxxx";string ss5 = ss4.PadLeft(6, '(');Console.WriteLine(ss5);String ss6 = ss5.PadRight(7, ')');Console.WriteLine(ss6);//获取字符串长度Console.WriteLine( ss6.Length+1);//删除字符串Console.WriteLine(ss4.Remove(3)); //从3之后字节开始删除Console.WriteLine(ss4.Remove(0,2));//删除0到字节//复制字符string ss7 = String.Copy(ss4);Console.WriteLine(ss7);//替换string b1 = ss4.Replace('x', 'c');Console.WriteLine(b1);//可变字符stringBuilder(字符串，分配大小)StringBuilder hostStr = new StringBuilder("窗前明月光，疑是地上霜",100);//结尾追加hostStr.Append("VS 举头望明月");Console.WriteLine(hostStr);//结尾追击2hostStr.AppendFormat("{0:s}", " 低头思故乡");Console.WriteLine(hostStr);//位置插入hostStr.Insert(0, "静夜思");Console.WriteLine(hostStr);//字符串替换hostStr.Replace("静夜思", "静夜思\t李白\t");Console.WriteLine(hostStr);//截取从0到。长度减去6的字符串hostStr.Remove(0, hostStr.Length - 6);Console.WriteLine(hostStr);Console.ReadLine();}} }

流程控值语句

using System; //多个命名空间。与python的import功能形似 using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Collections;namespace ConsoleApplication3 //建立命名空间 {class Program //类{static void Main(string[] args) {//if语句string str1 = "A";if (str1=="A"){Console.WriteLine("是的");}else if (str1=="B"){Console.WriteLine("不是");}//switch语句switch (str1){case "A":Console.WriteLine("是的A");break;case "B":Console.WriteLine("是的B");break;default:Console.WriteLine("都不是的");break;}//while语句while (str1.Length>0){Console.WriteLine("不是空值");break;}int i = 0;do{Console.WriteLine("当前值是：{0}",i);i++;} while (i<10);//forfor (int j = 0; j < 10; j++){Console.WriteLine("你好，{0}",j);}//foreach 语法ArrayList alt = new ArrayList();alt.Add("你");alt.Add("的");alt.Add("名");alt.Add("字");foreach (string item in alt){Console.WriteLine(item);}//continuefor (int k = 0; k < 5; k++){if (k==3){continue;}Console.WriteLine(k);}//goto语句ceshi1:Console.WriteLine("goto语句测试");goto ceshi1; //出现无限循环}} }

数据集合操作

using System; //多个命名空间。与python的import功能形似 using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Collections;namespace ConsoleApplication3 //建立命名空间 {class Program //类{static void Main(string[] args) {//数组int[] arr = new int[10];int[] brr = new int[] { 1,2,3,4,5,6,7,8,9,10};int[] crr = new int[] { 1, 22, 3, 43, 51, 6, 7, 8, 9, 10 };//二维数组int[,] erArr = new int[,] { { 1, 2 }, { 3, 4 } };int[,] erBrr = { { 1, 2 }, { 3, 4 } };int[,] erCrr = new int[2, 2] { { 1, 2 }, { 3, 4 } };for (int i = 0; i < brr.Length; i++){Console.WriteLine(brr[i]);}for (int j = 0; j < erBrr.GetLength(0); j++){for (int k = 0; k < erBrr.GetLength(1); k++){Console.WriteLine(erBrr[j,k]);}}//foreachforeach (int a3 in brr)Console.WriteLine(a3);//数组排序 正Array.Sort(crr);foreach (int a4 in crr)Console.WriteLine(a4);//数据排序 反Array.Reverse(crr);foreach (int a5 in crr)Console.WriteLine(a5);//数组合并int[] drr = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };int[] err = new int[] { 11,12,13,14,15 };int[] f = new int[drr.Length + err.Length];Console.WriteLine(f.Length);for (int q = 0; q < drr.Length; q++){f[q] = drr[q];}for (int w = 0; w < err.Length; w++){f[drr.Length+w] = err[w];}for (int ai = 0; ai < f.Length; ai++){Console.WriteLine(f[ai]);}//ArrayList高级动态数据int [] a1 = new int[] { 1, 2, 3, 4, 5, 6, 7 };ArrayList List = new ArrayList(a1);//Arraylist的固定大小判断Console.WriteLine(List.IsFixedSize);//是否为只读Console.WriteLine(List.IsReadOnly);//是否同步对ArrayList的访问Console.WriteLine(List.IsSynchronized);//获取索引值的元素Console.WriteLine(List[1]);//获取ArrayList访问的对象Console.WriteLine(List.SyncRoot);//Add方法List.Add(8);//获取ArrayList的长度，并追击到最后一个Console.WriteLine(List.Count);List.Insert(List.Count,9);//遍历输出for (int array = 0; array < List.Count; array++){Console.WriteLine(List[array]);}//遍历输出2foreach (int num1 in List){Console.WriteLine(num1);}//ArrayList的删除//搜索匹配的值，并删除List.Remove(8);//删除数字8//根据索引删除List.RemoveAt(0);//根据索引一处一定范围的List.RemoveRange(0, 3);foreach (int num1 in List){Console.WriteLine(num1);}List.Clear(); //清除数组所有Console.WriteLine("数组大小长度是{0}",List.Count);//Hashtable 哈希表的数组集合Hashtable hash = new Hashtable(); //实例化hash的对象hash.Add("id", "123");hash.Add("name", "ss");Console.WriteLine(hash.Count); //获取长度Console.WriteLine( hash["id"]);//获取指定值//判断是否包含keyBoolean iskeyvalue = hash.Contains("id");Boolean isKey = hash.ContainsKey("id");Console.WriteLine(isKey);//判断是否包含valueBoolean isValue = hash.ContainsValue("ss");Console.WriteLine(isValue);//获取所有键Console.WriteLine(hash.Keys);foreach (String key in hash.Keys){Console.WriteLine(hash[key].ToString());}foreach (String values in hash.Values){Console.WriteLine(values.ToString());}//删除//指定键位，删除hash.Remove("id");//清除所有hash.Clear();}} }

属性、方法、参数类型、重载

using System; //多个命名空间。与python的import功能形似 using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Collections;namespace ConsoleApplication3 //建立命名空间 {class Program //类{//自定义属性private string id = "";private string name = "";public string ID {get {return id;}set {id = value;}}public string Name{get { return name; }set { name = value; }}//params参数。对于可变的方法参数public void Username(params string[] list) {for (int i = 0; i < list.Length; i++){Console.WriteLine(list[i]);}}//ref参数，引用船值，即是传入变量，接收方法的返回值public void method(ref int i) {i = 200;}//out参数，引用船值，即是传入变量，接收方法的返回值public void methodOut(out int i){i = 200;}//静态方法public static void fangfa(){Console.WriteLine("静态方法，需要类名调用");}非静态方法public void fangfa1() {Console.WriteLine("非静态方法，通过实例调用");}//重载public int add(int a, int b) {return a + b;}public double add(double a, double b) {double c=a+b;return c;}static void Main(string[] args) {Program pro = new Program();pro.ID = "123";pro.Name = "zhang";Console.WriteLine("ID为{0},name为{1}",pro.id,pro.name);//param方法string[] s1 = new string[] { "zhang","王","李","你还哦" };pro.Username(s1);//ref方法int values = 1; //需要初始化值pro.method(ref values);Console.WriteLine(values);//out方法int outValue; //不需要初始化值pro.methodOut(out outValue);Console.WriteLine(outValue);//调用静态方法Program.fangfa();//调用非静态的方法pro.fangfa1();//重载方法调用Console.WriteLine(pro.add(1,2));Console.WriteLine(pro.add(1.1, 2.2));}} }

结构和类

using System; //多个命名空间。与python的import功能形似 using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Collections;namespace ConsoleApplication3 //建立命名空间 {//结构public struct Rect {public double w;public double h;public double Area() {return w * h;}}//构造函数与析构函数public class publics {public Double a1 = 123.1;public Double a2 = 123.123;public Double a3;//构造函数与类名一样public publics(){a3 = a1 + a2;}//析构函数~~publics(){Console.WriteLine("已经释放了publics的调用");}}//封装、继承、多态public class myClass{private int a = 0;private int b = 0;public int A{set {a = value;}get {return a;}}public int B{set{b = value;}get {return b;}}public int Add() {return a + b;}}//继承public class myClass1 : myClass {private int c;public int C{set{c = value;}get{return c;}}public int Add2() //这个方法就可以做为多态的一种{return A + B+C;}}class Program //类{static void Main(string[] args){//使用结构体Rect rect;rect.w = 123.123;rect.h = 1234.123;Console.WriteLine("面积为{0}",rect.Area());//调用publics体验构造函数和析构publics cs=new publics();Console.WriteLine(cs.a3);//使用类，体验封装，继承，多态myClass my1 = new myClass();my1.A = 123;my1.B = 345;Console.WriteLine(my1.Add());myClass1 my2 = new myClass1();my2.A = 123;my2.B = 456;my2.C = 120;Console.WriteLine(my2.Add2());}} }

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