libxcom.a is a concise and readable C++ template library.

The template library includes vector, list, stack, hash, map, bitset, graph, matrix,

There is also several linear programming solvers, include 
  exact simplex based on rational arithmetic,
  the approximate method based on double/float arithmetic, 
  the 0-1 integer programming solver, 
  and the mixed integer programming solver.

It is well implemented and able to build whole compiler, or anyother project.