Programming Inheritance and Polymorphism: A Practice

I. Overview:

You need to develop a monthly payroll program for a company. The programming task in the following requires the use of inheritance and polymorphism in the monthly payroll program. The figures-and-polymorphism sample project you studied earlier can serve as the basic framework of the payroll program. You may reuse and adapt the code in the figures-and-polymorphism sample project to help you set a basic framework, but you need to write everything on your own to make it work.

II. Context of the payroll program:

Company X has three categories of employees and pays the employees in different ways.

(i) Full time staff: an employee in this category receives a fixed monthly pay each month according to the contract,

(ii) Hourly workers: an employee in this category is paid by hour according to the work hours he/she got this month and the hourly rate stated in the contract, and

(iii) Sales persons: an employee in this category receives a fixed monthly base salary according to the contract and in addition for each new customer he/she brings to the company he/she receives an additional $1000 commission.

III. Programming Task:

Company X wants a payroll program that creates a two-level class hierarchy and uses polymorphism to handle monthly payroll processing in the following way:

1. Create an Employee class that has a string data member id for recording the employee id, an int data member monthlyPay for storing the employee’s pay this month, and three virtual methods getBasicInfo( ), calculateMonthlyPay( ), printMonthlyPay( ) to get the basic information of the employee for this month, to calculate the current monthly pay, and to print the current monthly pay + the basic information of the employee respectively.
2. Derive from the Employee class a FullTimer class that has an additional data member fixedSalary for recording the employee’s fixed monthly salary and implement accordingly the methods getBasicInfo( ), calculateMonthlyPay( ), printMonthlyPay( ) to get the basic information of the employee for this month, to calculate the current monthly pay, and to print the current monthly pay + the basic information of the employee respectively.
3. Derive from the Employee class a HourlyWorker class that has two additional data members workHours for recording the employee’s work hours this month and hourlyRate for recording the employee’s hourly rate this month and implement accordingly the methods getBasicInfo( ), calculateMonthlyPay( ), printMonthlyPay( ) to get the basic information of the employee for this month, to calculate the current monthly pay, and to print the current monthly pay + the basic information of the employee respectively.
4. Derive from the Employee class a SalesPerson class that has two additional data members baseSalary for recording the employee’s fixed monthly base salary and numberOfNewCustomers for recording the number of new customers the salesperson got this month and implement accordingly the methods getBasicInfo( ), calculateMonthlyPay( ), printMonthlyPay( ) to get the basic information of the employee for this month, to calculate the current monthly pay, and to print the current monthly pay + the basic information of the employee respectively.
5. Write a main function that (1) declares a vector of pointers to Employee for storing pointers to dynamically created Employee objects and (2) provides a menu of three services, i.e. adding a new employee, calculate the current monthly pay for every employee, and display the current monthly pay + the basic information of the employee for every employee as described in vi, vii, and viii below.
6. Add a new employee: Continue from v above. If the user chooses to add a new employee record, the main function should (1) ask the user what type of employee the person belongs to, and then (2) dynamically create a new object of the corresponding child class derived from the Employee class and call the object to run its getBasicInfo( ) member function to get the specific basic information of the new employee from the user. Store the pointer to the new object in the vector of pointers to Employee objects.
7. Calculate the current monthly pay: Continue from v above. If the user chooses to calculate the current monthly pay for every employee, the main function should iterate through the vector of pointers to Employee objects and call each object to run its own calculateMonthlyPay( ) member function to calculate the current monthly pay and store it in the monthlyPay data member.
8. Display the current monthly pay + basic information for every employee: Continue from v above. If the user chooses to print the current monthly pay + the basic information of the employee for every employee, the main function should iterate through the vector of pointers to Employee objects and call each object to run its printMonthlyPay( ) member function to print the current monthly pay + the basic information of the employee.

IV. Testing your implementation:

Run and test your program:

· add several employees, including all three categories (full-timer, hourly workers, and salespersons) in the mix,

· ask the program to calculate the current monthly pay, and

· ask the program to display the current monthly pay + basic information to see whether it can do the job correctly for employees in all three categories correctly.