How to learn coding efficiently from scratch?

Answer 1

According to me you should firstly learn the basics and complete the course from sololearn. If you'll have any doubt you can ask here.
Then you can check your skills in codeplayground.
Play some challenges to learn more.

and NEVER GIVE UP 😎

Answer 2

Scratch.
It's just,
blocks.
Translate each block into an algo
Translate the algo into C++!

Answer 3

learn the basics then find other source for advance techniques.