Matrices

Does anyone know where I can find the source code that does adding, subtract, multiplying, and dividing matrices by overloading operators and using vectors and arrays?

I'm learning it and the book only has a part of the code. It'd be a great help if I can actually see what it looks like and play around with it.

Thanks.

You can try:

http://math.nist.gov/mv++/

There is also Blitz.

A search for linear algebra libraries will probably yield a lot of good results as well.