what is arduino written in
The arduino language is really great for beginners, but have some limitations (e.g. you must have all your files in the same folder). And it is basically a simplification of C/C++ (you can practically copy&paste arduino code to a C/C++ file, and it will work).n fact many of the libraries are written in C++. Much of the underlying system is not object oriented, but it could be. Thus, The arduino language is C++ or C. C++ is not garbage collected.