Use Doxygen to generate documents and diagrams or graphs for your source code

$ sudo apt update
$ sudo apt install doxygen dia graphviz

$ cd [SOME_PATH]
$ doxygen -g

OUTPUT_DIRECTORY = [YOUR_OUTPUT_DIRECTORY]
INPUT = [YOUR_SOURCE_CODE]
RECURSIVE = YES
EXTRACT_ALL = YES
EXTRACT_PRIVATE = YES
EXTRACT_STATIC = YES
CLASS_DIAGRAMS = YES
DIA_PATH = /usr/bin/dia
HAVE_DOT = YES
CLASS_GRAPH = YES
COLLABORATION_GRAPH = YES

$ doxygen [YOUR_Doxyfile]