parent function manipulating member of derived class

[ljw2602]

Hi. I've been trying to solve this problem for many days, but I couldn't find a good solution or design pattern..

I have this inheritance hierarchy,

struct Base{...};
struct Derived1{...};
struct Derived2{...};

And then I have this inheritance hierarchy, where child classes have vector of different classes.

struct Child{
vector<Derived1*> x;
void common1(); ... void commonN();
};

struct Child2{
vector<Derived2*> x;
void common1(); ... void commonN();
void unique();
};

So there is this kind of relationship,

Base
Derived1 <--> Child1
Derived2 <--> Child2

Child1 and Child2 have many common functions (e.g. common1, ... commonN), but each class has its own unique functions too. These functions usually manipulate the vector x.

I attempted to put Child1 and Child2 under a parent class, so that I can put all common functions in the parent class. However, I confronted some obstacles such as:
1) If I create a parent class and have it contain all common functions, the common functions should have access to vector members of the derived classes. I don't think it is doable..

Overall, can you please give me any advice on what would be the best strategy to solve code duplication and inheritance problem??

[fcantoro]

you can use a template as base class, that accepts the vector element type and :

template <typename elem>
struct Child
{
	std::vector<elem*> x;
	void common1(); 
	void commonN();
};

struct Child1 : Child<Derived1>
{
};

struct Child2 : Child<Derived2>
{
	void unique();
};

[ljw2602]

Exactly!
I just figured that template base class might be what I want to use.
Now I feel more comfortable cause you confirmed my guess. Thank you :)

Just out of curiosity, is this design have any particular name?