C++Talk.NET

Charles-Antoine Giuliani · Guest

Hello to all!

First I would like to thank all of you for the support you provide ;-)

I am trying to write an adapter for some classes, and among other
things, give them a clone function. However the clone function does
not call the copy constructor but a default constructor which I did
not generate. The template adapter and interface look like this:

class TSDateInterface {
public:
virtual ~TSDateInterface(void) {};
virtual TSDateInterface* Clone(void) const = 0;
virtual std::string Str(void) const = 0;
};

template <typename T> class TSDateStandardAdapter : public
TSDateInterface {
public:
TSDateStandardAdapter(void) : storedDate_(NULL) {};
TSDateStandardAdapter& operator = (const
TSDateStandardAdapter& other) {
TSDateStandardAdapter ake(other);
Swap(ake, *this);
};
TSDateStandardAdapter(const T& toT) : storedDate_(new T(toT))
{};
virtual ~TSDateStandardAdapter(void)
{delete storedDate_;};
virtual TSDateStandardAdapter* Clone(void) const
{ return new TSDateStandardAdapter(*this);};
virtual std::string Str(void) const
{ return storedDate_->Str(); };
T* storedDate_;
private:
void Swap(TSDateStandardAdapter& other) {
T* temp = other.storedDate_;
other.storedDate_ = storedDate_;
storedDate_ = temp;
};
};

However when I compile this code and make the following assignment :
TSDateStandardAdapter<TSDateImplYear>* zz(new

TSDateStandardAdapter<TSDateImplYear>(TSDateImplYear(2001)));
cout << zz->Str() << ' ';
TSDateInterface* zz2 = zz->Clone();
cout << zz2->Str() << ' ';
delete zz;
cout << zz2->Str() << ' ';

The last zz2->Str() gives me an invalid value.

When debugging the code, the clone function does not call the copy
constructor from TSDateAdapter but another generated constructor. (I
am using visual c++ 7.1)

What am I doing wrong ?

Thanks in advance,

Charles

For reference, class TSDateImplYear is something like that:

class TSDateImplYear {
public:
TSDateImplYear (ticktype toy=
std::numeric_limits<ticktype>::min()) : year_(toy)
{ };
std::string Str(void) const {
std::ostringstream str;
str << year_;
return (str.str());
};
private:
ticktype year_;
};

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Maxim Yegorushkin · Guest

On 30 Jan 2005 18:52:28 -0500, Charles-Antoine Giuliani
<apprentice_99 (AT) hotmail (DOT) com> wrote:

B. Perlman · Guest

Hi. I will include just the constructors in your class, as you posted
it, with annotations:
default constructor:

Charles-Antoine Giuliani · Guest

Thanks a lot. This was pretty stupid from me, I feel shameful Wink

I
tried to debug this code for 3 hours, absolutely convinced I had
written a copy constructor, whereas I had a conversion constructor...
Now it works fine ;-)

Charles

On 31 Jan 2005 15:12:36 -0500, "B. Perlman" <batya (AT) excalibur (DOT) co.il>
wrote: