I am trying to implement Header Files with Source Files using C++, but in the terminal the give me some errors.
Here is the code:
main.cpp
#include <iostream> #include "add.h" using namespace std; int main() { cout << "The Sum of 3 and 4 is: " << add(3,4) << endl; return 0; } add.cpp
int add(int x, int y) { return (x + y); } add.h
#ifndef ADD_H #define ADD_H int add(int x, int y); #endif Terminal Messages: 
Try g++ -o add.o add.cpp followed by g++ -o HeaderTest main.cpp add.o.
Your code in C++ is perfectly fine. What you need is probably some adjustments in building. You should either read on how to build, i.e. compile and link manually or use some IDE, or at least build system like Make, CMake, QMake etc. If you want to do this by hand please provide command you have used to build this sample.
You did use the C-compiler. The warning tells you that you provide C++-code to the C-compiler. In case you want to get rid of this warning, try clang++ -o add.o add.cpp followed by clang++ -o HeaderTest main.cpp add.o
#include "add.h"fromadd.cpp. Second, the error message you pointed is apparently more related to the way you invoke clang than to the code itself.