is it compulsary to learn c language if we alredy know c++ langyage

Answer 1

no

Answer 2

... which are en vogue now

Answer 3

Here you see that c is procedure oriented language
and c++ is object oriented language(partially). There is no compulsion to learn. But there is no harm in learning c.

Answer 4

Not really imo.
Except you are planning to get into embedded systems

Answer 5

I also searching for this.