類別繼承

Person類別是用以對「真實世界(real world)」中的「人」進行「抽象對映(mapping abstraction)」的定義。

• [-] firstname : string
• [-] lastname : string

• [+] set_firstname(string fn) : void –> setter for firstname
• [+] get_firstname():string –> getter for firstname
• [+] set_lastname(string fn) : void –> setter for lastname
• [+] get_lastname():string –> getter for lastname
• [+] showInfo(): void –> print out its information

• Person() –> set default values of firstname and lastname as “unknown”
• Person(string fn, string ln) –> set firstname and lastname as fn and ln
• ~Person() –> print out that it has been deleted!

Student是繼承自Person類別的類別，用以對「真實世界(real world)」中的「學生」進行「抽象對映(mapping abstraction)」的定義。但比起Person類別，Student類別又更為特別一些，它還多了一個名為ID的data member及相關的setter與getter:

• [-] firstname : string
• [-] lastname : string
• [-] ID : string

• [+] set_firstname(string fn) : void –> setter for firstname
• [+] get_firstname():string –> getter for firstname
• [+] set_lastname(string fn) : void –> setter for lastname
• [+] get_lastname():string –> getter for lastname
• [+] showInfo(): void –> print out its information
• [+] set_ID(string id): void –> setter for ID
• [+] get_ID(): string –> getter for Id

None

#include <iostream>
using namespace std;

#ifndef _PERSON_
#define _PERSON_

class Person
{
private:
  string firstname;
  string lastname;

public:  
  Person();
  Person(string, string);
  ~Person();
  void showInfo();
  
  void set_firstname(string fn);
  string get_firstname();
  
  void set_lastname(string ln);
  string get_lastname();  
};
#endif

#include "person.h"

Person::~Person()
{
  cout << "A Person is removed." << endl;
}

Person::Person()
{
  cout << "A Person is created." << endl;
}

Person::Person(string fn, string ln)
{
  firstname=fn;
  lastname=ln;
}

void Person::showInfo()
{
  cout << "Name: " << firstname << " " << lastname << endl;
}

void Person::set_firstname(string fn)
{
  firstname=fn;
}

void Person::set_lastname(string ln)
{
  lastname=ln;
}

string Person::get_firstname()
{
  return firstname;
}

string Person::get_lastname()
{
  return lastname;
}

#ifndef _STUDENT_
#define _STUDENT_
#include "person.h"

class Student : public Person
{
private:
  string ID;
  
public:
  Student();
//  Student(string fn, string ln, string id);
  ~Student();
  void set_ID(string id);
  string get_ID();
};
#endif

#include "student.h"

Student::Student()
{
  cout << "A Student is created." << endl;
}

Student::~Student()
{
  cout << "A Student is removed." << endl;
}

void Student::set_ID(string id)
{
  ID=id;
}

string Student::get_ID()
{
  return ID;
}

#include <iostream>
using namespace std;

#include "student.h"

int main()
{
  Student *amy = new Student();
  
  amy->set_firstname("Amy");
  amy->set_lastname("Chang");
  amy->set_ID("s111418099");
  
  Student *tony = new Student(*amy);
  
  tony->set_firstname("Tony");  
  
  amy->showInfo();
  tony->showInfo();

  delete amy;
  delete tony;
  
  return 0;
}

all: person.o student.o
	g++ main.cpp person.o student.o -o main

person.o: person.cpp person.h
	g++ -c person.cpp
	
student.o: student.cpp student.h
	g++ -c student.cpp

clean:
	rm -f *.o main *.*~ *~