I had used GLPK a few years ago for solving a constrained MIP problem programmatically and liked it a lot. It has a C interface and uses an easy-to-use MathProg

I had used GLPK a few years ago for solving a constrained MIP problem programmatically and liked it a lot. It has a C interface and uses an easy-to-use MathProg language. When you look at your data and problems from the point of view of linear optimization theory, GLPK becomes a really handy tool.