Compiling C++ Using Terminal

Prerequisites

• GCC compiler
  • For Windows, you will need to install mingw
  • For Linux, you will need to refer to your distributions package manager
  • For Mac, you will need to use brew

Compiling C++ Using Terminal

1. First, let's make a simple C++ file named main.cpp

   // main.cpp
   #include <iostream>
   
   int main()
   {
     std::cout << "Hello World!\n";
   }
   

2. Now, open your terminal in the same directory where the file was saved.

3. To compile the file

   $ g++ main.cpp
   

   You can replace main.cpp with the filename you chose. This will compile your file into an executable called a.out

4. Finally, to run the file

   $ ./a.out
   

   

5. Incase you want to name the executable file

   $ g++ main.cpp -o main
   

   This will make the executable file as main

   

Compiling C++ Files with Header Files

You've divided your main file into multiple files. Now what?

1. I created a new file called Universe.hpp in includes directory and main.cpp into src directory My directory now looks like

   .
   ├── includes
   │   └── Universe.hpp
   └── src
       └── main.cpp
   

   // Universe.hpp
   #pragma once
   #include <iostream>
   
   class Universe
   {
     public:
       Universe() {
         std::cout << "Hello Universe\n";
       }
   };
   

   and I changed my main.cpp to

   // main.cpp
   #include <iostream>
   #include "Universe.hpp"
   
   int main()
   {
     std::cout << "Hello World!\n";
   
     Universe universe;
   }
   

   If I compile my main file now, I get an error

   

   What this means is that gcc can't find my Universe.hpp file, we need to tell where the file is.

2. To tell gcc where are header files are located, we will use -I flag

   $ g++ src/main.cpp -I includes
   

   It compiles just fine with no errors and runs as well!

Conclusion

1. g++ is used to compile C++ on terminal
2. -o flag is used to name output executable
3. -I is used to include header files directory