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2025-07-21 18:27:56

CSharp核心知识点学习

学习内容有：

绪论：面向对象的概念

Lesson1：类和对象

练习：

Lesson2：封装--成员变量和访问修饰符

练习:

Lesson3:封装--成员方法

Lesson4：封装--构造函数和析构函数

知识点四垃圾回收机制--面试常考

练习：

Lesson5：成员属性

练习：

Lesson6：封装--索引器

练习： using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Lesson6_练习 { #region 练习 //自定义一个整形数组类，该类中有一个整形数组变量 //为它封装增删查改的方法 class IntArray { private int[] array; //房间容量 private int capacity; //当前放了几个房间 private int length; public IntArray() { capacity = 5; length = 0; array = new int[capacity]; } //增 public void Add(int value) { //如果要增加就涉及扩容 //扩容就涉及"搬家" if(length < capacity) { array[length] = value; ++length; } //扩容“搬家” else { capacity *= 2; //新房子 int[] tempArray = new int[capacity]; for (int i = 0; i < array.Length; i++) { tempArray[i] = array[i]; } //老的房子地址指向新房子地址 array = tempArray; //传入的往后放 array[length] = value; ++length; } } //删 //指定内容删除 public void Remove(int value) { //找到传入值在哪个位置 for (int i = 0; i < length; i++) { if(array[i] == value) { RemoveAt(i); return; } } Console.WriteLine("没有在数组中找到{0}",value); } //指定索引删除 public void RemoveAt(int index) { if(index > length) { Console.WriteLine("当前数组只有{0}，你越界了",length); return; } for (int i = index; i < length - 1; i++) { array[i] = array[i + 1]; } --length; } //查改 public int this[int index] { get { if(index >= length || index < 0) { Console.WriteLine("越界了"); return 0; } return array[index]; } set { if (index >= length || index < 0) { Console.WriteLine("越界了"); } array[index] = value; } } public int Length { get { return length; } } } #endregion class Program { static void Main(string[] args) { Console.WriteLine("索引器练习"); IntArray intArray = new IntArray(); intArray.Add(1); intArray.Add(2); Console.WriteLine(intArray.Length); //intArray.RemoveAt(1); intArray.Remove(2); Console.WriteLine(intArray[0]); //Console.WriteLine(intArray[1]); Console.WriteLine(intArray.Length); } } } Lesson7：封装--静态成员

练习：

Lesson8：封装-- 静态类和静态构造函数

Lesson9：封装--拓展方法

练习：

Lesson10：封装--运算符重载

练习：

Lesson11：封装--内部类和分部类

Lesson12：继承--继承的基本规则

练习：

Lesson13：继承--里氏替换原则

练习：

Lesson14：继承--继承中的构造函数

练习：

Lesson15：继承--万物之父和装箱拆箱

练习：

Lesson16：继承--密封类

练习： using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Lesson16_练习 { #region 练习 //定义一个载具类 //有速度，最大速度，可乘人数，司机和乘客等，有上车，下车，行驶，车祸等方法 //用载具类申明一个对象，并将若干人装载上车 class Car { public int speed; public int maxSpeed; //当前装了多少人 public int num; public Person[] person; public Car(int speed, int maxSpeed, int num) { this.speed = speed; this.maxSpeed = maxSpeed; this.num = 0; person = new Person[num]; } public void GetIn(Person p) { if(num >= person.Length) { Console.WriteLine("满载了"); return; } person[num] = p; ++num; } public void GetOff(Person p) { for (int i = 0; i < person.Length; i++) { if(person[i] == null) { break; } if (person[i] == p) { //移动位置 for (int j = i; j < num - 1; j++) { person[j] = person[j + 1]; } //最后一个位置清空 person[num - 1] = null; --num; break; } } } public void Move() { } public void Boom() { } } class Person { } class Driver : Person { } class Passenger : Person { } #endregion class Program { static void Main(string[] args) { Console.WriteLine("封装继承综合练习"); Car car = new Car(80, 100, 20); Driver driver = new Driver(); Passenger p1 = new Passenger(); Passenger p2 = new Passenger(); Passenger p3 = new Passenger(); car.GetIn(driver); car.GetIn(p1); car.GetIn(p2); car.GetIn(p3); car.GetOff(p1); } } }

练习调试！！！

Lesson17：多态--vob

通过这节课的知识--解决了Lesson13 的练习题 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Lesson13_练习 { #region 练习一 //is和as的区别 //is 用于判断类对象判断是不是某个类型的对象 bool //as 用于转换把一个类对象转换成一个指定类型的对象 null #endregion #region 练习二 //写一个Monster类，它派生出Boss和Gobin两个类 //Boss有技能，小怪有攻击 //随机生成10个怪，装载到数组中 //遍历这个数组，调用他们的攻击方法，如果是boss就释放技能 class Monster { } class Boss : Monster { public void Skill() { Console.WriteLine("Boss释放技能"); } } class Goblin : Monster { public void Atk() { Console.WriteLine("小怪攻击"); } } #endregion #region 练习三 //FPS游戏模拟 //写一个玩家类，玩家可以拥有各种武器 //线在有四种武器，冲锋枪，散弹枪，手枪，匕首 //玩家默认拥有匕首 //请在玩家类中写一个方法，可以拾取不同的武器替换自己拥有的武器 class Weapon { public virtual string Input() { return null; } } /// <summary> /// 冲锋枪 /// </summary> class SubmachineGun : Weapon { public override string Input() { return "冲锋枪"; //Console.WriteLine("冲锋枪"); } } /// <summary> /// 散弹枪 /// </summary> class ShotGun : Weapon { public override string Input() { return "散弹枪"; //Console.WriteLine("散弹枪"); } } /// <summary> /// 手枪 /// </summary> class Pistol : Weapon { public override string Input() { return "手枪"; //Console.WriteLine("手枪"); } } /// <summary> /// 匕首 /// </summary> class Dagger : Weapon { public override string Input() { return "匕首"; //Console.WriteLine("匕首"); } } class Player { private Weapon nowHaveWeapon; public Player() { nowHaveWeapon = new Dagger(); } public void PickUp(Weapon weapon) { nowHaveWeapon = weapon; } public void Show() { Console.WriteLine("当前玩家使用的武器是：{0}",nowHaveWeapon.Input()); } } #endregion class Program { static void Main(string[] args) { Console.WriteLine("里氏替换原则练习"); //随机生成10个怪物 Monster[] objects = new Monster[10]; Random r = new Random(); int box = 0; for (int i = 0; i < objects.Length; i++) { box = r.Next(1, 3); if(box == 1) { objects[i] = new Boss(); } else { objects[i] = new Goblin(); } } //遍历数组 for (int i = 0; i < objects.Length; i++) { if(objects[i] is Boss) { (objects[i] as Boss).Skill(); } else if(objects[i] is Goblin) { (objects[i] as Goblin).Atk(); } } Player p = new Player(); p.Show(); Weapon submachineGun = new SubmachineGun(); p.PickUp(submachineGun); p.Show(); //遗留一个问题：重写？！！ //通过学习Lesson17--多态ovb 得以解决 } } }

练习： using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Lesson17_练习 { #region 练习一 //真的鸭子嘎嘎叫，木头鸭子吱吱叫，橡皮鸭子唧唧叫 class Duck { public virtual void Speak() { Console.WriteLine("嘎嘎叫"); } } class WoodDuck : Duck { public override void Speak() { //base.Speak(); Console.WriteLine("吱吱叫"); } } class RubberDuck : Duck { public override void Speak() { //base.Speak(); Console.WriteLine("唧唧叫"); } } #endregion #region 练习二 //所有员工9点打卡 //但经理十一点打卡，程序员不打卡 class Staff { public virtual void PunchTheClock() { Console.WriteLine("普通员工9点打卡"); } } class Manager : Staff { public override void PunchTheClock() { //base.PunchTheClock(); Console.WriteLine("经理11点打卡"); } } class Programmer : Staff { public override void PunchTheClock() { //base.PunchTheClock(); Console.WriteLine("程序员不打卡"); } } #endregion #region 练习三 //创建一个图形类，有求面积和周长两个方法 //创建矩形类，正方形类，圆形类继承图形类 //实例化矩形，正方形，圆形对象求面积和周长 class Graph { public virtual float GetLength() { return 0; } public virtual float GetArea() { return 0; } } class Rect : Graph { private float w; private float h; public Rect(float w, float h) { this.w = w; this.h = h; } public override float GetLength() { //return base.GetLength(); return 2 * (w + h); } public override float GetArea() { //return base.GetArea(); return w * h; } } class Square : Graph { private float h; public Square(float h) { this.h = h; } public override float GetLength() { //return base.GetLength(); return 4 * h; } public override float GetArea() { //return base.GetArea(); return h * h; } } class Circule : Graph { private float r; public Circule(float r) { this.r = r; } public override float GetLength() { //return base.GetLength(); return 2 * 3.14F * r; } public override float GetArea() { //return base.GetArea(); return 3.14f * r * r; } } #endregion class Program { static void Main(string[] args) { Console.WriteLine("多态ovb"); Console.WriteLine("virtual override base"); Duck d = new Duck(); d.Speak(); Duck wd = new WoodDuck(); wd.Speak(); Duck rd = new RubberDuck(); rd.Speak(); Staff s = new Staff(); s.PunchTheClock(); Staff ma = new Manager(); ma.PunchTheClock(); (ma as Manager).PunchTheClock(); Staff pr = new Programmer(); (pr as Programmer).PunchTheClock(); Rect r = new Rect(2, 4); Console.WriteLine("矩形的周长是：" + r.GetLength()); Console.WriteLine("矩形的面积是：" + r.GetArea()); Square sq = new Square(4); Console.WriteLine("正方形的周长是：" + sq.GetLength()); Console.WriteLine("正方形的面积是：" + sq.GetArea()); Circule ci = new Circule(3); Console.WriteLine("圆的周长是：" + ci.GetLength()); Console.WriteLine("圆的面积是：" + ci.GetArea()); } } }

Lesson18：多态--抽象类和抽象方法

练习： using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Lesson18_练习 { #region 练习一 //写一个动物抽象类，写三个子类 //人叫、狗叫、猫叫 abstract class Animal { public abstract void Speak(); } class Person : Animal { public override void Speak() { Console.WriteLine("人在说话"); } } class Dog : Animal { public override void Speak() { Console.WriteLine("狗在汪汪叫"); } } class Cat : Animal { public override void Speak() { Console.WriteLine("猫在喵喵叫"); } } #endregion #region 练习二 //创建一个图形类，有求面积和周长两个方法 //创建矩形类，正方形类，圆形类继承图形类 //实例化矩形，正方形，圆形对象求面积和周长 abstract class Graph { public abstract float GetLength(); public abstract float GetArea(); } class Rect : Graph { private float w; private float h; public Rect(float w, float h) { this.w = w; this.h = h; } public override float GetLength() { //return base.GetLength(); return 2 * (w + h); } public override float GetArea() { //return base.GetArea(); return w * h; } } class Square : Graph { private float h; public Square(float h) { this.h = h; } public override float GetLength() { //return base.GetLength(); return 4 * h; } public override float GetArea() { //return base.GetArea(); return h * h; } } class Circule : Graph { private float r; public Circule(float r) { this.r = r; } public override float GetLength() { //return base.GetLength(); return 2 * 3.14F * r; } public override float GetArea() { //return base.GetArea(); return 3.14f * r * r; } } #endregion class Program { static void Main(string[] args) { Console.WriteLine("抽象类和抽象方法"); Person p = new Person(); p.Speak(); Dog dog = new Dog(); dog.Speak(); Animal cat = new Cat(); cat.Speak(); } } } Lesson19：多态--接口

练习：重要，加深对接口的应用 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Lesson19_练习 { #region 练习一 //人、汽车、房子都需要登记，人需要到派出所登记，汽车需要去车管所登记，房子需要去房管局登记 //使用接口实现登记方法 interface IRegister { void Register(); } class Person : IRegister { public void Register() { Console.WriteLine("派出所登记"); } } class Car : IRegister { public void Register() { Console.WriteLine("车管所登记"); } } class Home : IRegister { public void Register() { Console.WriteLine("房管局登记"); } } #endregion #region 练习二 //麻雀、鸵鸟、企鹅、鹦鹉、直升机、天鹅 //直升机和部分鸟能飞 //鸵鸟和企鹅不能飞 //企鹅和天鹅能游泳 //除直升机，其他都能走 //请用面向对象相关知识实现 abstract class Bird { public abstract void Walk(); } interface IFly { void Fly(); } interface ISwimming { void Swimming(); } //麻雀 class Sparrow : Bird,IFly { public void Fly() { } public override void Walk() { } } //鸵鸟 class Ostrich : Bird { public override void Walk() { } } //企鹅 class Penguin : Bird,ISwimming { public void Swimming() { throw new NotImplementedException(); } public override void Walk() { } } //鹦鹉 class Parrot : Bird,IFly { public void Fly() { throw new NotImplementedException(); } public override void Walk() { } } //天鹅 class Swan : Bird,IFly,ISwimming { public void Fly() { throw new NotImplementedException(); } public void Swimming() { throw new NotImplementedException(); } public override void Walk() { } } //直升机 class Helicopter : IFly { public void Fly() { throw new NotImplementedException(); } } #endregion #region 练习三 //多态来模拟移动硬盘、U盘、MP3插到电脑上读取数据 //移动硬盘与U盘都属于存储设备 //MP3属于播放设备 //但他们都能插在电脑上传输数据 //电脑提供一个USB接口 //请实现电脑的传输数据的功能 interface IUSB { void ReadData(); } class StorageDevice : IUSB { public string name; public StorageDevice(string name) { this.name = name; } public void ReadData() { Console.WriteLine("{0}传输数据",name); } } class MP3 : IUSB { public void ReadData() { Console.WriteLine("MP3传输数据"); } } class Computer { public IUSB usb1; } #endregion class Program { static void Main(string[] args) { Console.WriteLine("接口练习"); IRegister p = new Person(); p.Register(); Car car = new Car(); car.Register(); Home home = new Home(); home.Register(); StorageDevice hd = new StorageDevice("移动硬盘"); StorageDevice ud = new StorageDevice("U盘"); MP3 mp3 = new MP3(); Computer cp = new Computer(); cp.usb1 = hd; cp.usb1.ReadData(); cp.usb1 = ud; cp.usb1.ReadData(); cp.usb1 = mp3; cp.usb1.ReadData(); } } }

Lesson20：多态--密封方法

Lesson21：面向对象相关--命名空间

练习：

Lesson22：面向对象相关--万物之父中的方法

练习：

Lesson23：面向对象相关--string

练习：

Lesson24：面向对象相关--StringBuilder

练习：

Lesson25：面向对象相关--结构体和类的区别

Lesson26：面向对象相关--抽象类和接口的区别

学习完成：