how can I learn c++ online and how it is good
Dear applicant considering the pandemic situation now-a-days all the short term courses like this are mostly carried out online. Now there are some online platforms like Coursera, Udemy, HP, Udacity, IBM which offer online courses taught by Experienced faculties of foreign universities like Stanford University, Duke University etc. You get to learn a lot by sitting at your home only, with certification. It is indeed good for your future, to increase your chances of selection during interviews.
Good luck!!