libGenome is a freely available toolkit for developing bioinformatic related
software in C++. It is intended to take the hassle out of performing common
tasks on genetic sequence and annotation data.

Among other things, libGenome can help you:
   - Read and write Multi-FastA format files
   - Read and write GenBank flat file database entries
   - Append, chop, truncate, reverse, complement, translate, and otherwise
     mangle sequence data
   - Access annotation in GenBank flat files

WWW: http://pages.cs.wisc.edu/~darling/libgenome/