重構, 第一個案例---（原始C++代码）---這是一個影片出租店用的程式

重構, 第一個案例
Refactoring, a First Example

這是一個影片出租店用的程式，計算每位顧客的消費金額並列
印報表（statement）。操作者告訴程式：顧客租了哪些影片、租期多長，程式便
根據租賃時間和影片類型算出費用。影片分為三類：普通片、兒童片和新片。除
了計算費用，還要為常客計算點數；點數會隨著「租片種類是否為新片」而有不
同。
我以數個classes 表現這個例子?的元素。圖1.1 是一張UML class diagram（類別
圖），用以顯示這些classes。

// reactor_MovieRent.cpp : Defines the entry point for the console application.

//


#include "stdafx.h"


#include "stdio.h"


#define snprintf _snprintf
/*
int main(int argc, char* argv[])
{
return 0;
}
*/


// movie-ref.cpp : Defines the entry point for the console application.
//
#include
#include
#include


using namespace std;
//  Refactoring, a First Example, step7, (~p52)


enum TYPE
{
  REGULAR,
  NEW_RELEASE,
  CHILDRENS
};


class Price
{
public:
  virtual int getPriceCode () = 0;
  virtual double getCharge (int daysRented) = 0;


  int getFrequentRenterPoints (int daysRented)
  {
    return 1;
  }


};


class ChildrensPrice:public Price
{
public:
  int getPriceCode ()
  {
    return CHILDRENS;
  }


  double getCharge (int daysRented)
  {
    double result = 1.5;
    if (daysRented > 3)
      result += (daysRented - 3) * 1.5;
    return result;
  }
};


class NewReleasePrice:public Price
{
public:
  int getPriceCode ()
  {
    return NEW_RELEASE;
  }


  double getCharge (int daysRented)
  {
    return daysRented * 3;
  }


  int getFrequentRenterPoints (int daysRented)
  {
    return (daysRented > 1) ? 2 : 1;
  }
};


class RegularPrice:public Price
{
public:
  int getPriceCode ()
  {
    return REGULAR;
  }


  double getCharge (int daysRented)
  {
    double result = 2;
    if (daysRented > 2)
      result += (daysRented - 2) * 1.5;
    return result;
  }
};


class Movie
{
private:
  string _title;  //movie name
  Price *_price;  //price code


public:  
  //default construtor for `Rental::Rental(Movie&, int)'
  Movie ()
  {
    _title = "unname";
    setPriceCode (0);
  }
  
  Movie (string title, int priceCode)
  {
    _title = title;
    setPriceCode (priceCode);
  }
  
  Movie (const Movie& movie)
  {
    _title = movie._title;
    setPriceCode (movie._price->getPriceCode());
  }
  
  ~Movie()
  {
    delete _price;
  }


  int getPriceCode ()
  {
    return _price->getPriceCode ();
  }


  void setPriceCode (int arg)
  {
    switch (arg)
    {
      case REGULAR:
        _price = new RegularPrice ();
      break;
      case CHILDRENS:
        _price = new ChildrensPrice ();
      break;
      case NEW_RELEASE:
        _price = new NewReleasePrice ();
      break;
      default:
        cout << "Incorrect Price Code" << endl;
      break;
      }
  }


  string getTitle ()
  {
    return _title;
  }


  double getCharge (int daysRented)
  {
    return _price->getCharge (daysRented);
  }


  int getFrequentRenterPoints (int daysRented)
  {
    return _price->getFrequentRenterPoints (daysRented);
  }
};


class Rental
{
private:
  Movie _movie;
  int _daysRented;


public:
  Rental (Movie& movie, int daysRented)
  {
    _movie = movie;
    _daysRented = daysRented;
  }


  int getDaysRented ()
  {
    return _daysRented;
  }


  Movie getMovie ()
  {
    return _movie;
  }


  double getCharge ()
  {
    return _movie.getCharge (_daysRented);
  }


  int getFrequentRenterPoints ()
  {
    return _movie.getFrequentRenterPoints (_daysRented);
  }
};


typedef vector < Rental > Vector;
typedef vector < Rental >::iterator Reniter;


class Customer
{
private:
  string _name;
  Vector _rentals;


public:
    Customer (string name)
  {
    _name = name;
  }


  void addRental (Rental& arg)
  {
    _rentals.push_back (arg);
  }


  string getName ()
  {
    return _name;
  }


  string statement ()
  {
    Reniter iter;
    char amount[32];
    string result =
      string ("Rental Record for ") + getName () + string ("\n");


    for (iter = _rentals.begin (); iter != _rentals.end (); ++iter)
    {
      Rental each = *iter;
      // show figures for this rental
      snprintf (amount, 32, "%f\n", each.getCharge ());
      result += string ("\t") + each.getMovie ().getTitle () 
        + string ("\t") + string (amount);
    }
      // add footer lines
    snprintf (amount, 32, "%f\n", getTotalCharge ());
    result += string ("Amount owed is ") + string (amount);
    snprintf (amount, 32, "%d", getTotalFrequentRenterPoints ());
    result += string ("You earned ") + string (amount) +
      string (" frequent renter points");
    return result;
  }


  string htmlStatement ()
  {
    Reniter iter;
    char amount[32];
    string result =
      string ("

Rentals for ") + getName () +
      string ("

\n");


    for (iter = _rentals.begin (); iter != _rentals.end (); ++iter)
    {
      Rental each = *iter;
      // show figures for this rental
      snprintf (amount, 32, "%f
\n", each.getCharge ());
      result += each.getMovie ().getTitle () + string (":") + string (amount);
    }


    // add footer lines?    
    snprintf (amount, 32, "%f

\n", getTotalCharge ());
    result += string ("

You owe ") + string (amount);
    snprintf (amount, 32, "%d frequent renter points

",
       getTotalFrequentRenterPoints ());
    result += string ("On this rental you earned ") + string (amount);
    return result;
  }


  int getTotalFrequentRenterPoints ()
  {
    int result = 0;
    Reniter iter;
    for (iter = _rentals.begin (); iter != _rentals.end (); ++iter)
    {
      Rental each = *iter;
      result += each.getFrequentRenterPoints ();
    }
    return result;
  }


  double getTotalCharge ()
  {
    double result = 0;
    Reniter iter;
    for (iter = _rentals.begin (); iter != _rentals.end (); ++iter)
    {
      Rental each = *iter;
      result += each.getCharge ();
    }
    return result;
  }


};


int
main (int argc, char *argv[])
{
  cout << "Refactoring, a First Example, step7" << endl;


  Movie m1 = Movie ("Seven", NEW_RELEASE);
  Movie m2 = Movie ("Terminator", REGULAR);
  Movie m3 = Movie ("Star Trek", CHILDRENS);


  Rental r1 = Rental (m1, 4);
  Rental r2 = Rental (m1, 2);
  Rental r3 = Rental (m3, 7);
  Rental r4 = Rental (m2, 5);
  Rental r5 = Rental (m3, 3);


  Customer c1 = Customer ("jjhou");
  c1.addRental (r1);
  c1.addRental (r4);


  Customer c2 = Customer ("gigix");
  c2.addRental (r1);
  c2.addRental (r3);
  c2.addRental (r2);


  Customer c3 = Customer ("jiangtao");
  c3.addRental (r3);
  c3.addRental (r5);


  Customer c4 = Customer ("yeka");
  c4.addRental (r2);
  c4.addRental (r3);
  c4.addRental (r5);


  cout << c1.statement () << endl;
  cout << c2.statement () << endl;
  cout << c3.statement () << endl;
  cout << c4.statement () << endl;


  return 0;
}