How to divide code into multiple .cpp files C++

Question

I want to create a function outside the main.cpp file i've tried creating a header file but it doesn't work:

Main.cpp:

#include "other.h"
int main() {
    MyFunc();
}

Other.cpp

#include <iostream>
#include "other.h"
void MyFunc() {
    std::cout << "Ohai from another .cpp file!";
    std::cin.get();
}

Other.h

#include <iostream>
#include "other.cpp"
void MyFunc();

nor CPP, G++, GCC compiler work

most likely a dupe of: https://stackoverflow.com/questions/3202136/using-g-to-compile-multiple-cpp-and-h-files — NathanOliver, Jun 11 '20 at 20:14
Read the following manual [about linking](https://www.learncpp.com/cpp-tutorial/introduction-to-the-compiler-linker-and-libraries/) — Victor Gubin, Jun 11 '20 at 20:15
Does this answer your question? [C++ - Compiling multiple files](https://stackoverflow.com/questions/41066437/c-compiling-multiple-files) — lancegerday, Jun 11 '20 at 21:10

Rohan Bari · Accepted Answer · 2020-06-12T04:38:00.170

1

You must include a header file and not a C++ file.

And therefore, you need to remove:

#include "other.cpp"

from other.h & use the following command-line for compiling:

g++ -o output main.cpp other.cpp

You'll get it linked and then compiled, then everything should be working fine.

edited Jun 12 '20 at 04:38

answered Jun 11 '20 at 20:28

Rohan Bari

No, this is backwards. The implementation file should `#include` the header file; the header should not `#include` the implementation file. The problem here is misunderstanding the C++ compilation model. Each source file is separate, and gets compiled on its own. The resulting object files get linked and you have a program. You don't `#include` all your source files into one massive beast. – Pete Becker Jun 11 '20 at 21:54
@PeteBecker You're right. We must use `.h` or `.hpp` file, not a `cpp` in `#include`. – Rohan Bari Jun 12 '20 at 04:38
Much better! +1. – Pete Becker Jun 12 '20 at 12:37

score 0 · Answer 2 · answered Jun 11 '20 at 20:16

0

You must remove #include "other.cpp" in header file.

answered Jun 11 '20 at 20:16

Anton Anisimov

score -1 · Answer 3 · answered Jun 11 '20 at 20:15

-1

erase the line "#include "other.cpp" in your other.h and you will be fine...

Edit: you also need a header guard...

answered Jun 11 '20 at 20:15

Huy Pham

Could you please advice the explained solution of translation units, and linking. – Victor Gubin Jun 11 '20 at 20:19

3 Answers3