It’s content is the best and there is a plenty of other Computer Science subjects too on their website like C,C++, python etc. DBMS, Operating Systems, Computer Networks etc.
This website and his youtube channel is awesome for any programming language and any development stuff, any technology you want to learn is available on his channel.
This is a very renowned institute in the field of coding, they provide premium courses which you can purchase and learn from. They provide very useful content through their courses. Even I have taken their free trial of C++ programming which has taught me up to the best.
Another good course on C++ is on educative website, it provide a really good user experience and covers the topics in detail, you can check the course here
For practicing you can go to hackerrank,C+ and can practice any topic related to C++ by selecting subdomain and difficulty levels, within few weeks you’ll notice a great change in your language proficiency.
For taking part in contest in C+ and can practice any topic related to C++ by selecting subdomain and difficulty levels and upgrade your level.
This website also provide you with good content to learn language. So you can go with this also.
CPlusplus is another excellent website for learning C++. Although this website also has some tutorials, its true potential shines as a reference.
EDABIT is a useful website for testing your C++ knowledge. It will give you a series of challenges to solve using C++, ranging from simple addition and division tasks to very hard challenges.
Learncpp is an excellent place for both beginners and experienced programmers to get started with C++.This website is practically an entire C++ course in itself.