We encapsulate SEP's Fortran90 data structure for handling data with an irregular spatial sampling (SEPlib90) in a C++ class representation (IGF90) and provide it with an interface to a C++ library of inversion and optimization algorithms. The IGF90 class provides a mechanism for users to take advantage of the efficient Fortran90 data structures and the object-oriented programming paradigm of C++. We present different examples to illustrate the IGF90 class user interface. We use the IGF90 class and the C++ library of optimization algorithms to solve a missing data problem given a roughening filter. We discuss the design of the C++/Fortran90 interface, and illustrate it with the C++ interface to SEP's Fortran90 data structure and the interface to a Fortran90 operator.