Question

I am in need of mixing C code with C++ code in a computer simulation.

A C library has functions which take references to a regular array of doubles:

void position(double[3])

Another C library defines its own vector type:

void do_something(*custom_vector)

And my front-end (in C++) uses boost::numeric::ublas::vector.

In the first case, I have a lot of places with this kind of code:

double tmp[3];
position(tmp)
boostvec r(3);
r(0) = tmp[0]; r(1) = tmp[1]; r(2) = tmp[2];
// continue working with r

also

custom_vector *v;
do_something(v);
boostvec r(3);
r(0) = v[0]; r(1) = v[1]; r(2) = v[2];

Internally, all the types are ultimately vector containers, but their slight implementation differences are causing a lot of boilerplate explosion. I am also dealing with a lot different versions of double (some define realtype (which is a double), others define number (which is a double), etc).

How do you deal with this situation?

Thank you.

Answer 1

As long as both source and destination types support the standard iterator interface (which is true for std::vector, arrays, and every Boost sequence type I can think of; so you just need to fix your custom_vector), and as long as there are implicit conversions possible between the numeric types, you should be able to just use std::copy.