How can I add function at other file? #12552

I am using ubuntu within VirtualBox from windows10.

For example, how can I use "CheckProofOfWork" function from pow.cpp at chainparams.cpp?

I added #include "pow.h" at chainparams.cpp, but after this and when I tried compile with 'make' at terminal, error says there is no definition of that function...

Is this C++'s linker problem? Then how to solve this?

This is a place to report issues, not for learning basic C++.

You may find help on sites like stackoverflow.