intarray library in
intarraylib.h and
intarraylib.cpp?
MarksStruct.cpp is a better monolithic
version, that uses are more a intelligent data type and an extended set
of functions for accessing the data type.
Extract the smart_integer_array data type and the functions
into a smartintarray library.
You will have to create the files smartintarraylib.h and smartintarraylib.cpp.
Rebuild the program and make sure it works as before.