Installing a C/C++ compiler

In order to compile and link C++ (or C) source code into an executable program, you need to install a compiler on your computer. How you do this will depend on your operating system and on your preferred method of software installation.

Installing a C/C++ compiler on macOS

Depending on how particular you are about which compiler (or compiler version) you wish to install, there are a few different options for installing a C/C++ compiler on your macOS system.

Installing a compiler with the Xcode command-line tools

The Xcode command-line tools are a good choice if you simply want some C/C++ compiler and aren't picky about which one. This is probably true if you are beginning to learn C/C++ (e.g., as a student in COSC 1020 at Georgetown University). The command-line tools include many programs, one of which is the LLVM compiler named clang (usually said aloud as "klang").

Installing a compiler with Homebrew

If you are picky compilers (or compiler versions), then the Homebrew package manager will give you control over exactly what you want to install. Both the GCC and LLVM toolchains are available.

Note that Homebrew requires the Xcode command-line tools in order to function. To avoid conflicts with the compiler that comes with the tools, Homebrew does not install to /usr/bin (typically, it installs to /usr/local/bin instead). Be sure to set your PATH, environment variables, and/or makefile variables appropriately to use the compiler you want.

Note also that Homebrew does not cross-alias between GCC and LLVM tools like the Xcode command-line tools, so you need to install and explicitly invoke the compiler you want to use.

Installing a C/C++ compiler on Windows

The WinLibs project is a free, open-source C/C++ compiler providing native implementations of GCC (and, optionally, of LLVM/clang) as a stand-alone installation. This works both for GUI development environments like Visual Studio Code and for CLI invocations through CMD.exe or Powershell.

The instructions below provide a few different options for installing WinLibs on your computer.

Installing WinLibs with winget

You can use the Windows Package Manager to install Winlibs with a terminal command. There are a few options to chose from; the first one listed below is best unless you know you need one of the others (if you know, you know).

Winget may need several minutes when "Extracting archive..." as WinLibs is delivered as a compressed archive of many small files (which takes time to extract and install properly). Have patience!

Installing WinLibs as a downloadable archive

If you prefer to download and install WinLibs yourself, you can do so via the instructions below. These are, more or less, the steps that winget performs (see above) but gives you more control over the installation directory.

1. Download the WinLibs archive
   1. Go to winlibs.com and scroll down to the "Download" section of the page.
   2. Look for the "Release Versions" / "UCRT runtime" section and find the first bullet point, labeled "(LATEST)" which includes the most recent version of GCC.
      • You can choose an older version of GCC and/or scroll down to the "MSVCRT runtime" if your needs require.
   3. Look to the line labeled "Win64" and select the "Zip archive" link to download the .zip file.
      • The first link includes LLVM, while the second does not.
2. Extract the archive to the install directory of your choice
3. Extract the contents of the .zip to "install" the compiler
   1. Select a directory on your computer which has only simple characters and no spaces in the folder/subfoldre names.
      • You'll remember for the following step -- I'll call it DIR in the next step. For example, I chose to install in D:\
   2. Extract the contents of the .zip file to your chosen directory. This will create a new folder named mingw64 (with several subdirectories).
4. Update your PATH
   1. Open the Start Menu and search for "Edit the system environment variables"
   2. In the window that appears, click the "Environment variables" button
   3. In the second window that appears, look in the bottom-half ("System Variables") for a row containing "Path"; click on this row, then push the "Edit" button
   4. In the third window that appears, click the "New" button to add a row to the bottom of the list of directories.
   5. In the new row, type DIR\mingw64\bin, where DIR is the directory you chose in the previous step. For example, I wrote D:\mingw64\bin
   6. Press the "OK" button on each of the three windows to save your settings
   7. Restart your computer for the updated path to take effect