- Both the eigen and armadillo libraries (linear algebra) use several modern C++ constructs. For instance, they use both expression templates to simplify arithmetic expressions and can sometimes eliminate some temporaries:
http://hpac.rwth-aachen.de/teaching/sem-accg-14/Armadillo.pdf (presentation on expression templates in Armadillo)
- The CGAL library (computational geometry) uses many modern C++ features (it heavily uses templates and specializations):