Do I need to provide a constructor for all possible combinations of input parameters?

Question

I have to write some code, but I don't know, how to do it in the easiest way.

In my program there are:

Class P
Class HP: public P
Class CP: public P
and class M

I have to write M construct with will be able to handle the diffrent combination of input arguments

for example:

HP hp("xxx", "yyy");
HP hp_1("xx1", "yy1");
CP cp("www", "aaa");
CP cp_1("ww1", "aa1");

M m(hp, hp1);
M m_1(hp, cp);
M m_2(cp_1, hp_1);
etc...

Any idea? Do I have write construct for each combination?

Answer 1

Well, as it seems from your question, the classes HP and CP have a common base class P. It totally depends on what M actually needs by differentiating HP and CP. If it's enough for M to use P's interface you can probably provide a (single) constructor for M using

 class M {
 public:
     M(P& a, P& b) {
         // Do whatever you didn't specify in your question
     }
     // Or pointer references if preferred
     M(P* a, P* b) {
         // Do whatever you didn't specify in your question
     }
 };

Even if you need to distinguish from HP and CP you can still use a dynamic_cast<> (for both variants mentioned) inside the constructors member initialization list or body.