Choosing a STL container with uniqueness and which keeps insertion ordering

Question

I am unable to decide which STL container to use in the following case:

1. I want to preserve the order of insertion of the elements
2. The elements in the

Answer 1

You could do this:

• Create a wrapper around your element class with two members: your element, and an index. Let's call it 'InsertedElement'. The index will be the insertion order.

• Define comparison operator for this class, which only takes into account your element, but not the index. This will ensure the uniqueness of elements, while remembering their insertion order.

• Wrap a std::set and an insertion counter in another class. Then, when you want to insert a new element, either:

• It already exists, nothing to do.
• It does not: insert it in the map while giving it the current max index + 1.

Something like:

class CMagicContainer
{
  public:
    std::set collection;
    int indexGenerator;

    ...
};