If interested in Financial Markets, Quantlib is interesting. https://github.com/lballabio/QuantLib https://github.com/lballabio/QuantLib Also, there is a book

If interested in Financial Markets, Quantlib is interesting. https://github.com/lballabio/QuantLib https://github.com/lballabio/QuantLib Also, there is a book which describes the different patterns used: https://leanpub.com/implementingquantlib https://leanpub.com/implementingquantlib