You can create new blank class diagrams and populate them with C/C++ projects or elements to examine structures and relationships of C/C++ applications.
The following is from the other topic: You can populate class diagrams by showing C/C++ elements that are related to each other by specific relationships.
You can select the relationship types based on how you want to show the related C/C++ elements and specify to what level you want to expand the related C/C++ elements.