NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c++-part1/446

Text File | 1996-08-05 | 4.4 KB | 177 lines

Path: ix.netcom.com!netnews
From: [e-mail](Robert A. Nannini )
Newsgroups: comp.lang.c++
Subject: Re: Using BC4.5 TArrayAsVector of my class in a class!
Date: 4 Jan 1996 16:24:55 GMT
Organization: Netcom
Message-ID: <4cgv0n$[e-mail]>
References: <[e-mail]>
NNTP-Posting-Host: ix-stl4-18.ix.netcom.com
X-NETCOM-Date: Thu Jan 04  8:24:55 AM PST 1996

In <[e-mail]> [e-mail] (Nicholas Arthur
Llewellyn) writes:
>
>This is my first use of BC4.5 and I'm trying to use the array class
>library to hold the class Card, in the class's Pack and Hand.
>
>I get the error:
>
>Compiling PROJECT.CPP:
>
><This is the one I'm trying to fix>
>Error PROJECT.CPP 71: Cannot find default constructor to initialize
>member 'pack' in function Pack::Pack()
>
><These other two I got from messing around trying to fix the above
>error>
>Error PROJECT.CPP 72: Type qualifier 'pack' must be a struct or class
>name in function Pack::Pack()
>Error PROJECT.CPP 72: Statement missing ; in function Pack::Pack()
>
>The Borland manuals are not much help, all the examples are too
>simple.
>
>Is there any one out there who can point in the correct direction?
>
>Here's the code:
>
>// Poker playing program v0.0
>// by N A Llewellyn
>
>#include <iostream.h>
>#include <classlib\arrays.h>
>
>// in order of rank from low to high
>enum RANK
>{two,three,four,five,six,seven,eight,nine,ten,jack,queen,king,ace};
>
>enum SUIT {clubs,harts,diamonds,spades}; // no order of rank
>
>enum FACE {up,down};
>
>class Card {
>
>    private:
>        RANK rank;
>        SUIT suit;
>        FACE face;
>
>    friend ostream& operator << (ostream&,const Card&);
>
>    public:
>        Card() {rank=two;suit=clubs;face=down;}
>        Card(const Card & c)
{rank=c.rank;suit=c.suit;face=c.face;}
>        int operator == (const Card & c) {return rank == c.rank;}
>        int operator < (const Card & c) {return rank < c.rank;}
>        void SetRank(RANK r) {rank=r;}
>        void SetSuit(SUIT s) {suit=s;}
>        void SetFace(FACE f) {face=f;}
>};
>
>typedef TSArrayAsVector <Card> CardArray;
>typedef TSArrayAsVectorIterator <Card> CardArrayIterator;
>
>class Pack {
>
>    private:
>        CardArray pack;
>        unsigned int NumberOfCards;
>
>    public:
>        Pack();
>        void AddCard(Card c) {pack.Add(c);NumberOfCards++;}
>        void FindAndDetach(Card c) {pack.Detach(c);}
>        void DetachFrom(int i) {pack.Detach(i);}
>        void FlushPack(void) {pack.Flush();NumberOfCards=0;}
>        int IsPackEmpty(void) {return pack.IsEmpty();}
>};
>
>class Hand {
>
>    private:
>        CardArray hand;
>        unsigned int NumberOfCards;
>
>    public:
>        Hand();
>        void AddCard(Card c) {hand.Add(c);NumberOfCards++;}
>        void FindAndDetach(Card c) {hand.Detach(c);}
>        void DetachFrom(int i) {hand.Detach(i);}
>        void FlushPack(void) {hand.Flush();NumberOfCards=0;}
>        int IsPackEmpty(void) {return hand.IsEmpty();}
>        ~Hand();
>};
>
>ostream& operator << (ostream& os,const Card& c)
>    {return os<<c.rank<<","<<c.suit<<","<<c.face;}
>
>// definition of constructor for Pack
>
>Pack::Pack()
>{
>    Card card;
>    SUIT suit;
>    RANK rank;
>
>    NumberOfCards=0;
>
>    for(suit=clubs;suit<=spades;suit++)
>        for(rank=two;rank<=ace;rank++)
>            {
>                card.SetSuit(suit);
>                card.SetRank(rank);
>                card.SetFace(down);
>                AddCard(card);
>                NumberOfCards++;
>            }
>}
>
>void Show(Card& c,void*)
>    {cout<<c<<endl;}
>
>void UseForEach(CardArray& c)
>    {c.ForEach(Show,0);}
>
>int main()
>{
>    Pack pack1;
>    UseForEach(pack1.pack);
>    return 0;
>}
>

You're running into this problem because Borland's TArrayAsVector class
does not have a default constructor.  For instance, when your Pack
class gets constructed, one of the first things the compiler does is
search for the constructor for each data member of the class. Since you
typedef'd your CardArray as a TArray, the compiler will search for
TArray's default constructor.  Since it doesn't have one, you get this
error message.

The way to solve it is to include your TArray in the initialization
list for the constructor of your Pack (and Hand) class. The code would
look like this:

----------
Pack::Pack() : pack(n1,n2,n3)
{
  //your constructor code
}
----------

Since your data member, pack, is a CardArray, it needs to have its
constructor specified in the initialization list, which resides after
the single colon.  The values n1, n2, and n3 are defined as:

n1:  Initial size of the array
n2:  Initial start point of the array (usually 0)
n3:  Number of extra array members to dynamically add if the array
grows beyond its inital bound.

Hope this helps.

bob
[e-mail]