4、定义一个Person类，它包含数据成员age、name和gender。从Person中派生一个类Employee，在新类中添加一个数据成员，存储个人的number。再从Employee中派生一个类Executive，每个派生类都应定义一个函数，来显示相关的信息（名称和类型，如"Fred Smith is an Employee"）。编写一个main()函数，生成两个数组，一个数组包含5个Executive对象，另一个数组包含5个一般的Employee对象，然后显示它们的信息。另外，调用从Employee类继承的成员函数，显示Executive的信息。
Person.h
// Person.h
// Person class and class derived from Person
#ifndef PERSON_H
#define PERSON_H
#include <string>
using std::string;
class Person {
public:
Person(): age(0), name(""), gender('f') {}; // Default constructor
Person(int theAge, string theName, char theGender);
void who() const; // Display details
protected:
int age; // Age in years
string name;
char gender; // 'm' or 'f'
};
class Employee: public Person {
public:
Employee() {}; // Default constructor - necessary to declare arrays
Employee(int theAge, string theName, char theGender, long persNum):
Person(theAge, theName, theGender), personnelNumber(persNum) {}
void who() const; // Display details
protected:
long personnelNumber;
};
class Executive: public Employee {
public:
Executive() {}; // Default constructor - necessary to declare arrays
Executive(int theAge, string theName, char theGender, long persNum):
Employee(theAge, theName, theGender, persNum) {}
void who() const; // Display details
};
#endifPerson.cpp
// Person.cpp
// Person class implementation
#include "Person.h"
#include <iostream>
#include <string>
using std::string;
using std::cout;
using std::endl;
Person::Person(int theAge, string theName, char theGender):
age(theAge), name(theName), gender(theGender) {
}
void Person::who() const {
cout << "\nThis is " << name << " who is " << age << " years old.";
}
void Employee::who() const {
cout << endl
<< name << " is a " << (gender == 'f' ? "female" : "male")
<< " employee aged " << age << ".";
}
void Executive::who() const {
cout << endl
<< name << " is a " << (gender == 'f' ? "female" : "male") << " executive.";
}
main.cpp
// main.cpp
// Working with Employee and Executive objects
#include <iostream>
#include "Person.h"
using std::cout;
using std::endl;
void main() {
Employee employees[5];
employees[0] = Employee(21, "Randy Marathon", 'm', 34567);
employees[1] = Employee(32, "Anna Pothecary", 'f', 34578);
employees[2] = Employee(46, "Peter Out", 'm', 34589);
employees[3] = Employee(37, "Sheila Rangeit", 'f', 34598);
employees[4] = Employee(65, "Jack Ittin", 'm', 34667);
int i = 0;
for (i=0; i<sizeof employees/sizeof(Employee); i++)
employees[i].who();
Executive executives[5];
executives[0] = Executive(44, "Irwin Pootlemeyer", 'm', 35567);
executives[1] = Executive(32, "Alexa Workwell", 'f', 35578);
executives[2] = Executive(42, "Steve Stove", 'm', 35589);
executives[3] = Executive(33, "Sue Neenuf", 'f', 35598);
executives[4] = Executive(29, "Melanie Clair", 'f', 35667);
for(i = 0 ; i<sizeof executives/sizeof(Executive) ; i++) {
executives[i].who();
executives[i].Employee::who();
}
cout << endl;
}