I love programming, I have bought many programming books (mostly C++) and have practiced a bunch online on various IDE's and websites such as sololearn.com and even worked as a software developer for a day.

Despite all that I still have questions about how programmers work, what are they supposed to know about the programming languages?
Are they expected to know all the complex stuff behind the IDE they work with?
What if they have questions themselves?
Are they required to know more than one programming language?