My teacher gave me four files. Two header files and two *.cpp files. This is not the first time this format of assignment has been given and I did not have any problems in the past. This is an N-Queens puzzle. main.cpp asks the board size, switches to queen.cpp which I have to edit, essentially functions, etc. The first *.h file links the functions to the main, and the second *.h file is to identify myself. I barely edited the files. I simply added some missing headers like #include <iostream>, etc. and this error pops up no matter what I do. Thank you, help is appreciated!