What is OOPS?
OOP usually stands for Object-Oriented Programming. Both Python and C++ (and further languages, such as Java, C#, etc) are object-oriented programming languages.
So no, C++ is not OOP, C++ is just one object-oriented language of many.
As for your original question: every program compiled and run on OnlineGDB will only allow console (standard output) to be displayed and no graphics. For graphics, it'd be probably best to install the desired programming language, IDE, libraries etc on your own computer or find other online sites that possibly support graphics to be displayed not just character output.