C++ can make use of native C libraries and header files. (As long as there is no incompatible stuff in the C implementation that will not compile as valid C++, there are only a few of these exceptions).
#include "c_header.h" will not work, however. Instead use the
extern keyword like so:
Then compile as follows:
g++ -c my_c_source.c my_main.cpp -o myExec.out
(remember to have the sources in the right order and before the executable!)