Here are the classes, structs, unions and interfaces with brief descriptions:

CcommandLineInterface	This class provides a command line interface for the Paillier cryptosystem. It is a singleton class, meaning that only one instance of it can exist at a time
CfilesystemCommon	A utility class providing functions to handle files and directories
CfilesystemPGM	Utility class for handling .pgm image files
Cimage_pgm	Methods to read and write PGM images with various bit depths
Cimage_portable	Base class for portable image formats. This class provides an interface for reading and writing portable image formats, such as PGM and PPM. It defines pure virtual methods for reading the number of lines and columns of an image, reading an image into a buffer, and writing an image from a buffer. Derived classes must implement these methods to provide support for a specific image format
Cimage_ppm	This class represents a PPM image and provides methods to read and write PPM images, and to extract their R, G, and B planes
CImageBase	This class is a base class for images. It provides some basic functionalities for images
CPaillier	This class implements the Paillier cryptosystem
CPaillierController	Superclass of Paillier main that contains common methods between subclasses
CPaillierControllerPGM	Controller for the Paillier cryptosystem applied to PGM images
CPaillierModel	This class represents a singleton model for the Paillier cryptosystem
CPaillierPrivateKey	Class representing the private key in the Paillier cryptosystem
CPaillierPublicKey	Class representing the public key in the Paillier cryptosystem