Splitting code into multiple files - Cheat Sheet & Quick Revision

Recall & Review

beginner

Why do we split C code into multiple files?

Splitting code into multiple files helps organize the program better, makes it easier to manage, and allows multiple people to work on different parts at the same time.

beginner

What is a header file (.h) used for in C?

A header file contains declarations like function prototypes and variable declarations that other files can use to know how to interact with the code without seeing the full details.

beginner

How do you include one file in another in C?

You use the #include directive with the file name in quotes for your own files, like #include "myfile.h".

beginner

What command compiles multiple C files together?

You can compile multiple files by listing them all in the compiler command, for example: gcc main.c utils.c -o program

beginner

What is the role of a .c file compared to a .h file?

A .c file contains the actual code (function definitions), while a .h file contains declarations (function prototypes and constants) to share with other files.

Which file type usually contains function declarations in C?

A .txt file

B .c file

C .exe file

D .h file

Header files (.h) contain declarations like function prototypes.

How do you tell the compiler to compile multiple C files together?

A List all .c files in the gcc command

B Use #include for .c files

C Put all code in one file

D Use a .h file only

You list all source files in the compiler command, like gcc main.c utils.c -o program.

What does #include "file.h" do in a C program?

A Copies the content of file.h into the current file

B Runs file.h as a program

C Compiles file.h separately

D Deletes file.h

#include literally inserts the content of the header file into the current file before compiling.

Why should you use header files in multi-file C programs?

A To store executable code

B To share declarations and avoid repeating code

C To make the program run faster

D To hide code from the compiler

Header files share declarations so multiple files know about functions and variables.

What happens if you forget to include a header file with function declarations?

A The program ignores the missing functions

B The program runs faster

C The compiler may give errors or warnings about missing functions

D The program compiles without any issues

Without declarations, the compiler doesn't know about the functions and will report errors.

Explain how to split a simple C program into two files: one for main and one for helper functions.

Think about separating code and sharing declarations.

Describe the difference between a .c file and a .h file and why both are important.

Focus on code vs declarations and sharing.