Answering this question for twenty years from now could be onerous.
So, there will still be C, and probably C++ as well, and not just in legacy systems like COBOL (which probably will still be around for legacy systems).
Top Programming languages
Organizations may even be normally victimization C18 and C++17 by then.
There additionally can most likely be all the opposite well-liked languages nowadays around, at least in the maintenance of legacy systems.
But I believe you are inquisitive regarding up and returning languages.
That’s harder to predict.
Even if a particular tiny language nowadays may be a massive language then it’ll have had twenty years of updates, making it probably quite different at that point.
But I can give some suggestions for languages around today that will have concepts and features that will make learning those languages useful.
One very likely type of language is those like Haskell.
You might even get either Haskell itself or a very similar language (but cleaned up with all the legacy support removed) be one of the top five by then.
Idris is another language value trying into for the long run.
It’s actually primarily based in some ways on Haskell, but the ways it uses dependant typing and the language features that go with dependent types will quite possibly be a
mainstream paradigm by then.
The last language I suggest learning is Elixir.
Even if it never becomes mainstream it is probably the easiest language today to learn the Actor Model that it borrows from Erlang, and that will certainly be in even higher use in 20 years than it is today.
What you know today will certainly be useful in 20 years, and at the very least you will be able to maintain legacy systems with them.
But these (and other) practical languages can give new ideas that may the little question be terribly helpful and outstanding within the decades to come back.