Rewrite C++ code

[fding]

Right now, the C++ code might allow for memory leaks. In particular, a new System object is created upon every call of simulate(). We should investigate what happens to the memory that is allocated, and whether or not to change it so that C++ also only has a simulate function.

[bgin]

Why you designed your solution as a C code? I wonder if you are making transition from FORTRAN 77 or from C to C++. You should at least try to wrap your code into classes and use Constructors instead of C-like init functions.