练习题
练习1：找错误
找错误1: 重写基类方法
public class BaseClass
{
public void ShowMessage()
{
Console.WriteLine("基类消息");
}
}
public class DerivedClass : BaseClass
{
public override void ShowMessage()
{
Console.WriteLine("派生类消息");
}
}找错误2: 重写基类方法
public class BaseClass
{
public virtual void ShowMessage()
{
Console.WriteLine("基类消息");
}
}
public class DerivedClass : BaseClass
{
public void ShowMessage()
{
Console.WriteLine("派生类消息");
}
}找错误3：重写基类方法
public class Animal
{
public virtual void Speak() { }
}
public class Dog : Animal
{
private override void Speak() { }
}练习2：交互式员工管理系统
虚方法重写练习，具有以下功能：
添加全职员工 - 输入姓名和月薪
添加兼职员工 - 输入姓名、工作小时和时薪
查看所有员工信息 - 显示所有已添加员工的基本信息
计算所有员工工资 - 计算并显示每个员工的工资及总工资
演示多态性 - 展示如何使用基类引用调用不同派生类的方法
退出系统
using System;
namespace InteractiveEmployeeSystem
{
// 基类：员工
class Employee
{
public string Name { get; set; }
// 虚方法：计算工资
public virtual double CalculateSalary()
{
return 0;
}
// 虚方法：显示信息
public virtual void DisplayInfo()
{
Console.WriteLine($"员工: {Name}");
}
}
// 全职员工类
class FullTimeEmployee : Employee
{
public double MonthlySalary { get; set; }
public override double CalculateSalary()
{
return MonthlySalary;
}
public override void DisplayInfo()
{
Console.WriteLine($"全职员工: {Name}, 固定月薪: {MonthlySalary}元");
}
}
// 兼职员工类
class PartTimeEmployee : Employee
{
public int WorkHours { get; set; }
public double HourlyRate { get; set; }
public override double CalculateSalary()
{
return WorkHours * HourlyRate;
}
public override void DisplayInfo()
{
Console.WriteLine($"兼职员工: {Name}, 工作小时: {WorkHours}, 时薪: {HourlyRate}元");
}
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine("=== 交互式员工管理系统 ===");
Console.WriteLine("练习虚方法重写和多态性");
Console.WriteLine();
bool running = true;
while (running)
{
Console.WriteLine("请选择操作:");
Console.WriteLine("1. 添加全职员工");
Console.WriteLine("2. 添加兼职员工");
Console.WriteLine("3. 查看所有员工信息");
Console.WriteLine("4. 计算所有员工工资");
Console.WriteLine("5. 演示多态性");
Console.WriteLine("6. 退出");
Console.Write("请输入选择 (1-6): ");
string choice = Console.ReadLine();
Console.WriteLine();
switch (choice)
{
case "1":
AddFullTimeEmployee();
break;
case "2":
AddPartTimeEmployee();
break;
case "3":
ShowAllEmployees();
break;
case "4":
CalculateAllSalaries();
break;
case "5":
DemonstratePolymorphism();
break;
case "6":
running = false;
Console.WriteLine("感谢使用员工管理系统，再见!");
break;
default:
Console.WriteLine("无效选择，请重新输入。");
break;
}
Console.WriteLine();
}
}
// 存储员工的数组
static Employee[] employees = new Employee[10];
static int employeeCount = 0;
// 添加全职员工
static void AddFullTimeEmployee()
{
if (employeeCount >= employees.Length)
{
Console.WriteLine("员工数量已达上限，无法添加新员工。");
return;
}
Console.Write("请输入员工姓名: ");
string name = Console.ReadLine();
Console.Write("请输入月薪: ");
if (double.TryParse(Console.ReadLine(), out double salary))
{
FullTimeEmployee emp = new FullTimeEmployee
{
Name = name,
MonthlySalary = salary
};
employees[employeeCount] = emp;
employeeCount++;
Console.WriteLine($"全职员工 {name} 添加成功!");
}
else
{
Console.WriteLine("输入的月薪无效，请重新操作。");
}
}
// 添加兼职员工
static void AddPartTimeEmployee()
{
if (employeeCount >= employees.Length)
{
Console.WriteLine("员工数量已达上限，无法添加新员工。");
return;
}
Console.Write("请输入员工姓名: ");
string name = Console.ReadLine();
Console.Write("请输入工作小时: ");
if (!int.TryParse(Console.ReadLine(), out int hours))
{
Console.WriteLine("输入的工作小时无效，请重新操作。");
return;
}
Console.Write("请输入时薪: ");
if (double.TryParse(Console.ReadLine(), out double rate))
{
PartTimeEmployee emp = new PartTimeEmployee
{
Name = name,
WorkHours = hours,
HourlyRate = rate
};
employees[employeeCount] = emp;
employeeCount++;
Console.WriteLine($"兼职员工 {name} 添加成功!");
}
else
{
Console.WriteLine("输入的时薪无效，请重新操作。");
}
}
// 显示所有员工信息
static void ShowAllEmployees()
{
if (employeeCount == 0)
{
Console.WriteLine("暂无员工信息。");
return;
}
Console.WriteLine("=== 所有员工信息 ===");
for (int i = 0; i < employeeCount; i++)
{
Console.Write($"{i+1}. ");
employees[i].DisplayInfo();
}
}
// 计算所有员工工资
static void CalculateAllSalaries()
{
if (employeeCount == 0)
{
Console.WriteLine("暂无员工信息。");
return;
}
Console.WriteLine("=== 员工工资计算 ===");
double totalSalary = 0;
for (int i = 0; i < employeeCount; i++)
{
double salary = employees[i].CalculateSalary();
Console.WriteLine($"{employees[i].Name} 的工资: {salary}元");
totalSalary += salary;
}
Console.WriteLine($"所有员工工资总额: {totalSalary}元");
}
// 演示多态性
static void DemonstratePolymorphism()
{
Console.WriteLine("=== 多态性演示 ===");
Console.WriteLine("创建不同类型的员工，但使用基类引用:");
// 使用基类引用指向不同类型的对象
Employee emp1 = new FullTimeEmployee { Name = "张三", MonthlySalary = 8000 };
Employee emp2 = new PartTimeEmployee { Name = "李四", WorkHours = 100, HourlyRate = 50 };
Console.WriteLine("使用相同的基类引用调用方法:");
Console.WriteLine();
Console.WriteLine("员工1:");
emp1.DisplayInfo();
Console.WriteLine($"计算工资: {emp1.CalculateSalary()}元");
Console.WriteLine();
Console.WriteLine("员工2:");
emp2.DisplayInfo();
Console.WriteLine($"计算工资: {emp2.CalculateSalary()}元");
Console.WriteLine();
Console.WriteLine("说明: 相同的调用方式(emp.DisplayInfo()和emp.CalculateSalary())");
Console.WriteLine("但根据对象的实际类型执行了不同的实现，这就是多态性!");
}
}
}