3 replies to this topic

[markrodgers11]

I am working on a text-based RPG and I defined a vector in my game.cpp file and now I am trying to access it from my inputSystem.cpp file, it shows that it is unknown? I am wondering how I can access this vector from this other .cpp files?

-Thanks

[greenvertex]

See the extern keyword.

[Nikko_Bertoa]

If your vector in game.cpp is

std::vector<someType> someName;

you should write in inputSystem.cpp

extern std::vector<someType> someName;

[Bregma]

Better yet, put the extern declaration in a header, and include that header in both .cpp files. That way, if either the declaration (in the header) or the definition (in game.cpp) gets changed bit the other does not, you get a compile failure instead of a mysterious runtime failure.

Also, putting shared variable declarations in header files documents them as being shared between .cpp files.