Header and source file organization - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of a header file in C?

A header file (.h) declares functions, macros, and variables so they can be shared between multiple source files (.c). It helps organize code and avoid repetition.

beginner

Why should function definitions be placed in source files (.c) instead of header files (.h)?

Function definitions in source files avoid multiple definition errors during linking. Header files should only have declarations to allow sharing without duplication.

intermediate

What is an include guard and why is it important?

An include guard is a set of preprocessor commands (#ifndef, #define, #endif) in a header file that prevents it from being included multiple times, avoiding redefinition errors.

beginner

How do you include a header file in a source file?

Use the #include directive with quotes for your own headers, like #include "myheader.h". This tells the compiler to insert the header's content.

intermediate

What is the benefit of separating declarations and definitions into header and source files?

Separating declarations and definitions improves code readability, allows multiple source files to share declarations, and helps manage large projects by modularizing code.

Which file should contain the function implementation in C?

A Header file (.h)

B Source file (.c)

C Makefile

D Executable file

Function implementations belong in source files (.c) to avoid multiple definitions and keep code organized.

What does an include guard prevent?

A Compilation errors from syntax mistakes

B Runtime errors

C Linker errors from missing functions

D Multiple inclusions of the same header file

Include guards prevent the same header file from being included more than once, avoiding redefinition errors.

How do you include a standard library header in C?

A #include <stdio.h>

B #include "stdio.h"

C #include (stdio.h)

D import stdio.h

Standard library headers are included with angle brackets, like #include .

Which of these is NOT typically found in a header file?

A Function declarations

B Macro definitions

C Function implementations

D Type definitions

Function implementations should be in source files, not header files.

Why use header files in a C project?

A To share declarations between source files

B To execute code

C To store compiled binaries

D To write comments

Header files share declarations so multiple source files can use the same functions and types.

Explain how header and source files work together in a C program.

Think about how you tell the compiler about functions before using them.

Describe the role and structure of an include guard in a header file.

It's like a safety check to avoid repeating the same code.