passing a class as a parameter c++

Question

Instead of doing this and keep on making redundant code for everything:

Molecule::Molecule(Hydrogenyx& h){
    //some code
}

Molecule::Molecule(Carbonyx& c){
    //same code as hydro
}

Molecule::Molecule(Sulphuryx& s){
    //same code
}

is there a way I can just make it so it can look like this?:

Molecule::Molecule(x){
    //code that can apply to all
}

Answer 1

is there a way I can just make it so it can look like this?:

Sure. You can use a member function template.

Declaration:

template <typename T> Molecule(T& t);

Implementation:

template <typename T>
Molecule::Molecule(T& t){
   // The common code.
}

Answer 2

An example of Ben cisneros comment would be the following:

class Example { 
  // shared code 
}

class Hydrogenyx : public Example { 
  // code for Hydrogenyx 
}  

With that you can do something like this:

Example* ex;
Hydrogenyx hx(/*Construcr things*/)
ex = &hx;

Functions like the ones you described would automatically up-cast the object.