面向对象编程与泛型编程---C++primer读书笔记

1.OOP的基础

2.书店应用程序案列

1.基类的定义

class Library{
public:
    bool check_out(const LibMember&);
    bool check_in(const LibMember&);
    bool is_late(const Date& today);
    double apply_fine();
    ostream& print(ostream& = cout);
    Date due_date() const;
    Date date_borrowed() const;
    string title() const;
    const LibMember& member() const;
};

class Item_base{
public:
    Item_base(const std::string &book = "",double sales_price = 0.0):
    isbn(book),price(sales_price){ }

    std::string book( ) const {return isbn;}

    virtual double net_price(std::size_t n) const
    { return n*price;}
    virtual ~Item_base() { }
private:
    std::string isbn;
protected:
    double price;   
};

void Bulk_item::memfcn(const Bulk_item &d,const Item_base &b)
{
    double ret = price;
    ret = d.price;
    ret = b.price;//error
}

2.定义派生类

class Bulk_item:public Item_base
{
public:
    double net_price(std::size_t) const;
private:
    std::size_t min_qty;
    double discount;
};