In this chapter, we took a single source file made up of many structures and functions that operate on them and grouped them into four source code files and four header files. We saw how we could—and should—group structures and functions that operate on them into a source file and a corresponding header file. All of the functions were related, in that they operated on the structures declared in that file's header file. These many source files were then compiled into a single program. We could then build programs with those multiple files. We also explored simple yet efficient ways to use the preprocessor without overusing it. Lastly, we saw how to build a multi-file program by specifying each .c file on the compiler command line.
This chapter is just an introduction to multi-file programs. In the next chapter, Chapter 25, Understanding Scope, we will expand our knowledge of multi-file programs so that we can both limit which variables and functions...
