I // Fig. 12.9: Employee.h 2 // Employee abstract base class. 3 #ifndef EMPLOYEE_H 4 #define EMPLOYEE_H 5 6 #include // C++ standard string class 7 8 class Employee { 9 public: Employee(const std::string&, const std::string&, const std::string &); virtual -Employee() - default; // compiler generates virtual destructor 10 II 12 13 void setFirstName(const std::string&); // set first name std::string getFirstName() const; // return first name 14 15 16 void setlastName (const std::string&); // set last name std::string getLastName () const; // return last name 17 18 19 void setSocialSecurityNumber(const std::string&); // set SSN std::string getSocialSecurityNumber () const; !/ return SSN 20 21 // pure virtual function makes Employee an abstract base class virtual double earnings () const 0; // pure virtual virtual std::string toString() const; // virtual private: std::string firstName; std::string lastName; std::string socialSecurityNumber; 22 23 24 25 26 27 28 29 }; 30 31 #endif // EMPLOYEE_H Fig. 12.9 Employee abstract base class. // Fig. 12.10: Employee.cpp 2 // Abstract-base-class Employee menber-function definitions. 3 // Note: No definitions are given for pure virtual functions. 4 #include 5 #include "Employee.h" // Employee class definition 6 using namespace std; 7 8 // constructor 9 Employee::Employee (const string& first, const string& last, const string& ssn) : firstName(first), lastName(last), socialsSecurityNumber(ssn) {} 10 II 12 // set first name 14 void Employee::setFirstName (const string& first) {firstName = first;} 13 15 16 // return first name 17 string Employee::getFirstName () const {return firstName;} 18 19 // set last name 20 void Employee::setLastName (const string& last) {lastName = last;} 21 22 // return last name string Employee::getlastName () const {return lastName;} 24 // set social security number void Employee::setSocialSecurityNumber (const string& ssn) { socialSecurityNumber = ssn; // should validate } 23 25 26 27 28 29 // return social security number string Employee::getSocialSecurityNumber() const { return socialSecurityNumber; 30 31 32 33 34 35 // tostring Employee's information (virtual, but not pure virtual) 36 string Employee::toString () const { return getFirstName() + " "s + getLastName ) + "\nsocial security number: "s + getSocialSecurityNumber(); 37 38 39 Fig. 12.10 Employee Class implementation file.