derived class setup

[zwA4jE8b]

I am making a queue based on an unordered linked list. I have an unorderedlinkedlist class and a linkedqueue class shown in the following code

#ifndef H_LINKQUEUE
#define H_LINKQUEUE

#include <assert.h>
#include "queue.h"
#include "unorderedlinkedlist.h"

template <class dType>
struct nodeType
{
	dType id;
	nodeType<dType> *link;
};

template <class dType>
class linkqueue: public queue<dType>, unorderedlinkedlist<dType>
{
	unorderedlinkedlist<dType> _Q;
public:
	linkqueue();
	bool isEmpty() const;
	bool isFull() const;
	void initqueue();
	dType front() const;
	dType back() const;
	void EnQ(const dType& _add);
	dType DeQ();
	~linkqueue();
};

template <class dType>
bool linkqueue<dType>::isEmpty() const {return (_count == 0);}

template <class dType>
bool linkqueue<dType>::isFull() const {return (_count >= _maxsize);}

template <class dType>
dType linkqueue<dType>::front() const
{
	assert(!isEmpty());
	
}

#endif 

as you can see on line 18 i declare an instance of the base class. Is this the correct way to implement it?

Thanks,
-Mike-

[guestgulkan]

Seems redundant to me - as linkqueue is derived from unorderedlinkedlist, so it already contains
an unorderedlinkedlist subobject.

So you have to decide whether:

1. To derive from unorderedlinkedlist and not have the unorderedlinkedlist variable.

2. Not to derive from unorderedlinkedlist and have an unorderedlinkedlist variable.

This depends on the relationship between the two classes.

[zwA4jE8b]

Ok, I think I would rather not have the variable. To do this do I use the above code, minus line 18, and call function from unorderedlinkedlist class as such

in the EnQ function I could call...

unorderedlinkedlist<dType>::insertlast(dType _add)

[zwA4jE8b]

I understand pretty well about making single classes, and some simple derivation.

Is something more like this what I need?
can anyone give me an example?

CubeType::CubeType(double h, double l, double w): RectangleType(l, w)
{
	height = new double;
	*height = h;
}

Thank you!