Multi index array

• Download demo project - 13 Kb

The Problem

Let's say that we have structure "Person" with attributes "Name", "Surname", "Age", etc. All "Persons" are kept in an array, and usually we need to find a person by name or surname or by another attribute.

Those who have read my article Extended collections is familiar with the CSortedArray class and knows its disadvantages:

• During sorting the array has changed the order of the array. Sometimes is very important that you don't change the order of the array in order to have the possibility for binary searching.

• It is possible sort only by one trait (individual characteristic)

We can conclude that the sorted array doesn't match our requirements, so I decided to implement a class which behaves as a simple array, but additionally supports binary search functionality.

The Multi Index Array

‘Multi Index Array' class supports:

• Array functionality, most of you will recognize MFC CArray
• Lookup - a binary search that returns -1 on failure.
• Search - a binary search that returns the nearest element on failure.
• SearchIndexRange - a binary search. If data is not unique then it returns a valid array index range

Why a MFC collection and not STL?

• Too many different implementations with different extensions.
• The best libraries are made by yourself :)

Anyway, I hope that it will be useful.