A multi-file program in C refers to a program that is organized into multiple source files (.c files), each containing a part of the program's code. The primary purpose of creating a multi-file program is to manage and modularize the codebase, making it more organized, maintainable, and scalable.

Here's a simple explanation of the components typically found in a multi-file C program:

1. Header Files (.h): Header files contain declarations of functions, structures, and other elements that are used across multiple source files.
2. Source Files (.c): Source files contain the actual implementation of functions, structures, and other code elements declared in the header files.
3. Makefile: A makefile is often used to automate the compilation and linking process for multi-file programs.

            
Sample code
             File: main.c
             
               #include 
               #include "functions.h"
               
               int main() {
                   int result = add(5, 3);
                   printf("Sum: %d\n", result);
                   return 0;
               }
               
             File:functions.h
             
               int add(int a,int b)
               {
               return a+b;
               }