Re: [Gnucap-devel] Need clarification regarding public functions from class CARD_LIST

[al davis]

On Thursday 31 July 2014, al davis wrote:
> clone() makes a copy of itself.

more info ....

clone is always defined something like this:

class FOO : public SOME_BASE {
//////
//////
SOME_BASE* clone()const {return new FOO(*this);}
/////
};

I might use it like this:

int main()
{
  FOO aa;
  FOO* bb = aa.clone();
  // now I have two of them
}

Since it is just a wrapper for the copy constructor, why not 
just use the copy constructor directly?

Answer, because I really don't know exactly what type to copy.  
clone() is virtual.

So I might have:

int main()
{
   CARD* prototype = device_dispatcher["resistor"];
   CARD* an_instance = prototype.clone();
   CARD* another_instance  = prototype.clone();

   // or I could use the short form:
   CARD* yet_another = device_dispatcher.clone("capacitor");
}