The Representation

How do you represent a set internally?

At first thought it might seem like a simple problem. The trivial solution is to have each set be a

collection $($e$.$g$.$ a vector$)$ of objects.

While this seems like a simple solution on face value, it can be horribly inefficient. What if I

wanted to make sets of media objects that were each unmanageably large?

A better solution is to store all possible set members, the so$-$called Universal or Master set,

within the object as a class $($static$)$ member. Each instantiated set would then be simply

composed of a collection of integers, which are simply pointers to the actual objects in the

Master set.

This sounds like a good idea. But there's an even better one. With a static master set, you still

have to initialize it by copying over the supplied elements into it$.$ With an understanding that

you will not change the master set, why not have your client $($the instantiator of the Set class$)$

create and maintain the master set as a vector, and you only deal with integer indices into this

$($externally maintained$)$ master set?

$4$

That's the approach we will take in this quest. Although you don't have to code a lot, most of the

time, I presume, may be taken up by simply wrapping your head around this:

$$ The Set object will contain a pointer to an externally maintained vector of elements we

call the master set. This pointer must be set during set initialization.

$$ Each Set object will contain a vector of integers, each of which is an index in the master

set to a valid element contained in that Set. $($See Figure $1)$class Set $1$

private:

vectoraT${?}_{\text{;}}\{\begin{array}{c}\frac{?}{?}\end{array}$

${?}^{**}$