A. 多态练习一工资系统

实现课本例9-3题目要求。根据4类不同员工类型分别进行工资的计算。

抽象基类Employee表示员工，这个类派生出SalariedEmployee、HourlyEmplyee和CommissionEmployee类，CommissionEmployee类派生出BasePlusCommissionEmployee类。（课本例9-3图）

1.固定工：每周工资一样，与工作时间长短无关，由SalariedEmployee类实现；

2.计时工：按时计酬，超过40小时算加班工资，由HourlyEmplyee类实现；

3.雇佣员工：按销售百分比例计算，由CommissionEmployee类实现；

4.底薪雇佣员工：在底薪之上增加销售百分比。在本期内，公司准备对底薪雇佣员工升薪10%，由BasePlusCommissionEmployee类实现。

在主函数中

创建4个派生类的对象，调用Earning(）方法输出。

多态的使用，创建含有4个派生类元素的Employee数组，调用Earning(）方法输出。

【注：】此题编译通过即可

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using System;
// Written by Sheauhaw Jang
// 2020-11-10 10:54:13
namespace CSharp_Week7_A
{
    abstract class Employee
    {
        public string Name { get; protected set; }
        public Employee(string namae) { Name = namae; }
        public abstract double GetSal();
        public virtual void Clear() { }
        public void WriteName() { Console.WriteLine(Name); }
        public void Earning() { Console.WriteLine(GetSal()); }
    }
    class SalariedEmployee : Employee
    {
        public double Bsal { get; set; }
        public SalariedEmployee(string namae, double x) : base(namae) { Bsal = x; Clear(); }
        public override double GetSal() { return Bsal; }
    }
    class HourlyEmployee : Employee
    {
        public double SalPrh { get; protected set; }
        public int WorkT { get; set; }
        public HourlyEmployee(string namae, double preh) : base(namae) { SalPrh = preh; }
        public void NoteWork(int t) { WorkT += t; }
        public override void Clear() { WorkT = 0; }
        const int HourLaw = 40;
        public override double GetSal() 
        {
            if (WorkT <= HourLaw)
                return SalPrh * WorkT;
            else
                return SalPrh * HourLaw + 1.5 * SalPrh * (WorkT - HourLaw);
        }
    }
    class CommissionEmployee : Employee
    {
        double Rate { get; set; }
        double ComVa { get; set; }
        public CommissionEmployee(string namae, double x) : base(namae) { Rate = x; }
        public override void Clear() { ComVa = 0; }
        public void NoteCom(double x) { ComVa += x; }
        public override double GetSal() { return ComVa * Rate; }
    }
    class BasePlusCommissionEmployee : CommissionEmployee
    {
        public double Bsal { get; set; }
        public BasePlusCommissionEmployee(string namae, double x, double r)
            : base(namae, r) { Bsal = x; }
        public override double GetSal() { return base.GetSal() + Bsal; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Employee[] eps = new Employee[4];
            SalariedEmployee epa = new SalariedEmployee("A", 10000);
            HourlyEmployee epb = new HourlyEmployee("B", 250);
            epb.NoteWork(50);
            CommissionEmployee epc = new CommissionEmployee("C", 0.05);
            epc.NoteCom(1e7);
            BasePlusCommissionEmployee epd = new BasePlusCommissionEmployee("D", 10000, 0.05);
            epd.NoteCom(1e7);
            eps[0] = epa;
            eps[1] = epb;
            eps[2] = epc;
            eps[3] = epd;
            foreach (Employee ep in eps)
            {
                ep.WriteName();
                ep.Earning();
            }
        }
    }
}

B. 工资系统+生日

修改例题9-3，在Employee类中添加新的字段birthDate表示员工的生日。（如：DateTime dt=new DateTime(2000,12,21)）

birthDate的数据类型为DateTime结构体类型（C#自带）。假设工资每月处理一次。

创建Employee数组，存储不同类型员工对象的引用。

可以循环输出每种类型员工的姓名和工资。如果本月是员工的生日，则工资增加100元。

【注：】本题编译通过即可。

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using System;
// Written by Sheauhaw Jang
// 2020-11-10 10:54:13
namespace CSharp_Week7_A
{
    abstract class Employee
    {
        public string Name { get; protected set; }
        public DateTime Birth { get; set; }
        public Employee(string namae) { Name = namae; Birth = new DateTime(1900, 1, 1); }
        public bool Bouns() { return DateTime.Now.Month == Birth.Month; }
        public abstract double GetSal();
        public virtual void Clear() { }
        public void SetBirth(int y, int m, int d) { Birth = new DateTime(y, m, d); }
        public void WriteName() { Console.WriteLine(Name); }
        public double GetTotSal() { return GetSal() + (Bouns() ? 100 : 0); }
        public void Earning() { Console.WriteLine(GetTotSal()); }
    }
    class SalariedEmployee : Employee
    {
        public double Bsal { get; set; }
        public SalariedEmployee(string namae, double x) : base(namae) { Bsal = x; Clear(); }
        public override double GetSal() { return Bsal; }
    }
    class HourlyEmployee : Employee
    {
        public double SalPrh { get; protected set; }
        public int WorkT { get; set; }
        public HourlyEmployee(string namae, double preh) : base(namae) { SalPrh = preh; }
        public void NoteWork(int t) { WorkT += t; }
        public override void Clear() { WorkT = 0; }
        const int HourLaw = 40;
        public override double GetSal() 
        {
            if (WorkT <= HourLaw)
                return SalPrh * WorkT;
            else
                return SalPrh * HourLaw + 1.5 * SalPrh * (WorkT - HourLaw);
        }
    }
    class CommissionEmployee : Employee
    {
        double Rate { get; set; }
        double ComVa { get; set; }
        public CommissionEmployee(string namae, double x) : base(namae) { Rate = x; }
        public override void Clear() { ComVa = 0; }
        public void NoteCom(double x) { ComVa += x; }
        public override double GetSal() { return ComVa * Rate; }
    }
    class BasePlusCommissionEmployee : CommissionEmployee
    {
        public double Bsal { get; set; }
        public BasePlusCommissionEmployee(string namae, double x, double r)
            : base(namae, r) { Bsal = x; }
        public override double GetSal() { return base.GetSal() + Bsal; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Employee[] eps = new Employee[4];
            SalariedEmployee epa = new SalariedEmployee("A", 10000);
            epa.SetBirth(1926, 8, 17);
            eps[0] = epa;
            HourlyEmployee epb = new HourlyEmployee("B", 250);
            epb.SetBirth(1997, 7, 1);
            epb.NoteWork(50);
            eps[1] = epb;
            CommissionEmployee epc = new CommissionEmployee("C", 0.05);
            epc.NoteCom(1e7);
            epc.SetBirth(2002, 8, 17);
            eps[2] = epc;
            BasePlusCommissionEmployee epd = new BasePlusCommissionEmployee("D", 10000, 0.05);
            epd.NoteCom(1e7);
            epd.SetBirth(2020, 11, 30);
            eps[3] = epd;
            foreach (Employee ep in eps)
            {
                ep.WriteName();
                ep.Earning();
            }
        }
    }
}

C. 工资系统+计件工

修改例题9-3，增加Employee类的另一个派生类PieceWorker，表示计件工。

PieceWorker类具有专用的实例变量wage和pieces分别表示每件的工资和生产的件数。

在PieceWorker类中提供Earning方法的具体实现，计算员工的收入。计算方法是将件数乘以每件的工资。

创建一个Employee数组，存储新的类层次中每个具体类对象的引用，显示每个员工收入。

【注：】本题编译通过即可。

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using System;
// Written by Sheauhaw Jang
// 2020-11-10 10:54:13
namespace CSharp_Week7_C
{
    abstract class Employee
    {
        public string Name { get; protected set; }
        public DateTime Birth { get; set; }
        public Employee(string namae) { Name = namae; Birth = new DateTime(1900, 1, 1); }
        public bool Bouns() { return DateTime.Now.Month == Birth.Month; }
        public abstract double GetSal();
        public virtual void Clear() { }
        public void SetBirth(int y, int m, int d) { Birth = new DateTime(y, m, d); }
        public void WriteName() { Console.WriteLine(Name); }
        public double GetTotSal() { return GetSal() + (Bouns() ? 100 : 0); }
        public void Earning() { Console.WriteLine(GetTotSal()); }
    }
    class SalariedEmployee : Employee
    {
        public double Bsal { get; set; }
        public SalariedEmployee(string namae, double x) : base(namae) { Bsal = x; Clear(); }
        public override double GetSal() { return Bsal; }
    }
    class HourlyEmployee : Employee
    {
        public double SalPrh { get; protected set; }
        public int WorkT { get; set; }
        public HourlyEmployee(string namae, double preh) : base(namae) { SalPrh = preh; }
        public void NoteWork(int t) { WorkT += t; }
        public override void Clear() { WorkT = 0; }
        const int HourLaw = 40;
        public override double GetSal()
        {
            if (WorkT <= HourLaw)
                return SalPrh * WorkT;
            else
                return SalPrh * HourLaw + 1.5 * SalPrh * (WorkT - HourLaw);
        }
    }
    class CommissionEmployee : Employee
    {
        double Rate { get; set; }
        double ComVa { get; set; }
        public CommissionEmployee(string namae, double x) : base(namae) { Rate = x; }
        public override void Clear() { ComVa = 0; }
        public void NoteCom(double x) { ComVa += x; }
        public override double GetSal() { return ComVa * Rate; }
    }
    class BasePlusCommissionEmployee : CommissionEmployee
    {
        public double Bsal { get; set; }
        public BasePlusCommissionEmployee(string namae, double x, double r)
            : base(namae, r) { Bsal = x; }
        public override double GetSal() { return base.GetSal() + Bsal; }
    }
    class PieceWorker : Employee
    {
        double wage { get; set; }
        int pieces { get; set; }
        public PieceWorker(string namae, double x) : base(namae) { wage = x; }
        public override void Clear() { pieces = 0; }
        public void NotePieces(int x) { pieces += x; }
        public override double GetSal() { return pieces * wage; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Employee[] eps = new Employee[5];
            SalariedEmployee epa = new SalariedEmployee("A", 10000);
            epa.SetBirth(1926, 8, 17);
            eps[0] = epa;
            HourlyEmployee epb = new HourlyEmployee("B", 250);
            epb.SetBirth(1997, 7, 1);
            epb.NoteWork(50);
            eps[1] = epb;
            CommissionEmployee epc = new CommissionEmployee("C", 0.05);
            epc.NoteCom(1e7);
            epc.SetBirth(2002, 8, 17);
            eps[2] = epc;
            BasePlusCommissionEmployee epd = new BasePlusCommissionEmployee("D", 10000, 0.05);
            epd.NoteCom(1e7);
            epd.SetBirth(2020, 11, 30);
            eps[3] = epd;
            PieceWorker epe = new PieceWorker("E", 100);
            epe.NotePieces(100);
            epe.SetBirth(2077, 12, 31);
            eps[4] = epe;
            foreach (Employee ep in eps)
            {
                ep.WriteName();
                ep.Earning();
            }
        }
    }
}

D. 类和接口

定义一个动物类Animal，包含字段姓名、年龄，有1个带参数的构造方法，初始化2个私有字段。抽象方法叫Shout();

鸽子类派生自Animal，新增私有字段羽毛（默认白色）；覆写方法Shout()，方法体输出相关信息（自己组织格式）*岁的鸽子姓名咕咕叫；

猫类派生自Animal，新增属性胡须长度；覆写方法Shout(），方法体输出相关信息（自己组织格式）*岁的小猫姓名喵喵叫；

定义一个交通工具类Vehicle，包含颜色，品牌。有1个无参数的构造方法，初始化2个私有字段（默认值自己给）。

派生类飞机继承Vehicle。新增飞行高度属性。

定义接口IFly，包含方法Fly()。鸽子类、飞机类均继承该接口，实现Fly()。鸽子类的Fly()方法，输出*颜色的鸽子飞。飞机类的Fly()方法输出*品牌的飞机飞行在*千米的高空。

在主函数中生成对象，测试类中的方法。

【注：】本题编译通过即可。

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using System;
// Written by Sheauhaw Jang
// 2020-11-10 11:12:50
namespace CSharp_Week7_D
{
    interface IFly
    {
        void Fly();
    }
    abstract class Animal
    {
        public string Name { get; set; }
        public int Age { get; set; }   
        public Animal(string namae, int x) { Name = namae; Age = x; }
        public abstract void Shout();
    }
    class Pigeon : Animal, IFly
    {
        public int Wing { get; set; }
        public Pigeon(string namae, int x) : base(namae, x) { Wing = 0xffffff; }
        public override void Shout() { Console.WriteLine("{0}岁的鸽子{1}咕咕叫", Age, Name); }
        public void Fly() { Console.WriteLine("{0}颜色的鸽子飞", string.Format("#{0:X}", Wing)); }
    }
    class Cat : Animal
    {
        public int Leng { get; set; }
        public Cat(string namae, int x) : base(namae, x) { Leng = 0; }
        public override void Shout() { Console.WriteLine("{0}岁的小猫{1}喵喵叫", Age, Name); }
    }
    class Vehicle
    {
        public int Color { get; set; }
        public string Company { get; set; }
        public Vehicle() { Color = 0xffffff; Company = "XJTU"; }
    }
    class Plane : Vehicle, IFly
    {
        public int Height { get; set; }
        public void Fly() { Console.WriteLine("{0}品牌的飞机飞行在{1}千米的高空", Company, Height); }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Pigeon zdk = new Pigeon("Zeondik", 18);
            zdk.Shout();
            zdk.Fly();
            Plane fakeloc = new Plane();
            fakeloc.Height = 114514;
            fakeloc.Fly();
        }
    }
}

E. *选做*——窗体程序“计算利率”

学习MOOC视频12.4例题计算利率，完成以下窗体程序。

要求：

1.熟悉Visual Studio新建Windows Form项目；

2.按照图示设计界面；

\3. 编写“确定”按钮的事件。

4.运行程序，输入“本金”、“利率”，选择“年龄”，点击“确定”按钮，“本息合计”显示计算结果。

【注】本题自愿完成。

解决方案