How to secure my code?

Hello everyone,
I am designing a GUI using MATLAB to interface with my FreeFem++ code.
Until now the GUI works properly only if the FreeFem++ file of the code exists in the same folder with the GUI file.
However, my problem is that I want to share my GUI with many users without letting them read the FreeFem++ code, I want them only to access it through the GUI.
Does anyone know how to handle his situation?
Thank you