Can you name some good websites for online learning of languages like C++, java etc.?

Answer 1

https://www.sololearn.com/Discuss/636195/?ref=app
https://www.sololearn.com/Discuss/208039/?ref=app
https://www.sololearn.com/Discuss/923664/?ref=app

Answer 2

https://www.tutorialspoint.com/

Answer 3

For C++:

An in-depth tutorial:
http://learncpp.com
A beginner's reference for the standard library:
http://www.cplusplus.com/reference/
A more technical, but also more useful and more complete, C/C++ reference:
http://en.cppreference.com

Also, there's "The C++ Programming Language, Fourth Edition" book which you can easily find online.