One of my friend requested me to add basic stuff related to C programming. Initially when I started coding I was skeptical using custom header files, using same variable in different .c files and building binary from multiple C files. This post probably clears all those doubts.
Below shapshot shows content in header file (praveen.h) and code in different C files (sharedvar1.c, sharedvar2.c).
Below snapshot shows how to compile multiple C files to create a single binary and also output of the program.
Also we have learned how to access single variable across multiple files.
Other articles on C language
Hope this might have helped from someone somewhere :) !!!