0

I'm self studying from the book, C++ Primer Plus Fifth Edition, by Stephen Prata. The following relates to Chapter 13, Page 699, Programming Exercise #4. One task is to write the derived class method definitions based upon the given prototypes. The following are the said prototypes.

class Port
{
    private:
        char *brand;
        char style[20];     // i.e. tawny, ruby, vintage
        int bottles;
    public:
        Port(const char *br = "none", const char *st = "none", int b = 0);
        Port(const Port &p);            // copy constructor
        virtual ~Port() { delete [] brand;}
        Port & operator=(const Port &p);
        Port & operator+=(int b);
        Port & operator-=(int b);
        int BottleCount() const {return bottles;}
        virtual void Show() const;
        friend ostream &operator<<(ostream &os, const Port &p);
};

class VintagePort : public Port
{
    private:
        char * nickname;            // i.e. The Noble, or Old Velvet, etc.
        int year;                   // vintage year
    public:
        VintagePort();
        VintagePort(const char *br, int b, const char *nn, int y);
        VintagePort(const VintagePort &vp);
        ~VintagePort() {delete [] nickname;}
        void Show() const;
        friend ostream & operator<<(ostream &os, const VintagePort & vp);
};

My problem relates to the constructors, lines 8 and 26, displayed again:

Port(const char *br = "none", const char *st = "none", int b = 0);
VintagePort(const char *br, int b, const char *nn, int y);

How can a method definition be correctly written if the argument list has a missing base class argument (as is the case here), which is required for the base class constructor.

2
Contributors
2
Replies
3
Views
9 Years
Discussion Span
Last Post by superjacent
0

the missing argument appears to be the one to initialize the style member. based on comments in the base class, i guess that you are expected to pass "vintage" as the style for VintagePort .

0

Thanks again. After posting this question, re-reading it, I sort of then realised that the missing argument had to be 'hardcoded' or be a 'string literal' at the definition. Probably the point of the exercise. In any event, it's making me think.

This question has already been answered. Start a new discussion instead.
Have something to contribute to this discussion? Please be thoughtful, detailed and courteous, and be sure to adhere to our posting rules.