If you are a student at 42, I advise you to watch the educational videos (pedago) on the intranet.
Les classes :
https://fr.wikibooks.org/wiki/Programmation_C%2B%2B/Les_classes (fr)
https://cpp.developpez.com/cours/cppavance/ (fr) (Coplien)
Les references :
https://fr.wikibooks.org/wiki/Programmation_C%2B%2B/Les_r%C3%A9f%C3%A9rences (fr)
https://codes-sources.commentcamarche.net/source/10304-difference-entre-pointeur-et-reference-par-un-exemple (fr)
Les strings :
http://www.cplusplus.com/reference/string/string/ (en)
https://en.cppreference.com/w/cpp/string/basic_string
File gestion :
https://webdevdesigner.com/q/read-file-contents-into-a-string-in-c-duplicate-60589/ (en)
Les operateurs :
https://openclassrooms.com/fr/courses/1894236-programmez-avec-le-langage-c/1897891-surchargez-un-operateur (fr)
Les heritages :
https://loic-joly.developpez.com/articles/heritage-multiple/ (fr)
https://www.geeksforgeeks.org/virtual-function-cpp/ (en)
https://fr.wikipedia.org/wiki/H%C3%A9ritage_multiple (fr)
Le polymorphisme :
https://openclassrooms.com/fr/courses/1894236-programmez-avec-le-langage-c/1898632-mettez-en-oeuvre-le-polymorphisme (fr)
Try-Catch :
https://en.cppreference.com/w/cpp/language/try_catch (en)
https://www.w3schools.com/cpp/cpp_exceptions.asp (en)
Random :
https://www.cplusplus.com/reference/cstdlib/rand/ (en)
Containers :
https://en.cppreference.com/w/cpp/container (en)
For all of your cpp projects I advise you to compile with :
$ clang++ -Wall -Wextra -Werror -std=c++98 #your_files.cpp