C Programming for Beginners #20 | multi-file programs and header files in C

C Programming for Beginners: Episode 20 of SyntaxPilot's free C full course, with real-life examples for every concept. multi-file programs and header files in C. In this video you'll learn: • Why one giant main.c doesn't scale • Splitting code into .c files • implicit declaration and undefined reference errors • Declarations vs definitions: function prototypes • Writing your own header file (.h) • #include "file.h" vs #include ‹file.h› • Include guards and #pragma once • extern: sharing a global variable • static: keeping a function private • Separate compilation: gcc -c, .o files and linking • A first Makefile • Mini project: a three-file bill splitter Every concept starts with a real-life example, then an animation and notes, then live code in the SyntaxPilot online compiler. Practice free in the SyntaxPilot compiler (nothing to install): https://syntaxpilot-learning-2026.web... Detailed notes for this episode (code, outputs, practice): https://syntaxpilot-learning-2026.web... Chapters 00:00 Welcome 00:23 Today's agenda 00:47 One cook, one giant file 01:59 Cut it into two files 03:28 Prototypes: declare before use 05:30 Your own header file 07:08 Include guards 09:03 extern and static 10:26 gcc -c, .o files and make 11:31 Mini project: a 3-file bill splitter 12:55 Common mistakes 13:22 Quick quiz 13:47 Recap and homework 14:21 Next episode Next episode: Debugging with gdb Post your homework and quiz answer in the comments, and subscribe for the full basic-to-master playlist, free. #CProgramming #CTutorial #SyntaxPilot