CS::SkipList Library is a C++ template library of containers based on skip lists. These containers work like sets and maps, but can also be accessed via numerical index. This collection has vector-like containers where all operations work in logarithmic time. It also has a composite container where you can order the same elements in many different ways at the same time.
TIXI is a fast and simple XML interface library for applications written in C, C++, Fortran, Java, and Python. Although simplified and somewhat restricted compared to a fully-fledged XML processing library, it can create documents, create and delete nodes, and add and remove element attributes. Routines for reading and writing text nodes and nodes holding integer and floating point numbers are included, along with routines that process aggregates of these simple types for the processing of geometric data, multidimensional arrays, or arrays of vectors.