In this book, we recommend free software whenever possible. This is important for user freedom, and this is one reason we recommend GCC throughout the book.
In addition, to MinGW GCC, the Clang C compiler is also open source and excellent quality. The code in this book was also tested to run successfully using Clang on Windows.
Command-line tools such as GCC and Clang are often easier to integrate into the complicated workflows required for larger projects. These open source tools also provide better standards compliance than Microsoft's compilers.
That said, the code in this book also works with Microsoft's compilers. The code was tested for both Microsoft Visual Studio 2015 and Microsoft Visual Studio 2017.