Header File Locations

The compiler follows specific rules to find header files, and we can configure additional search paths. Let's break this down:

When looking for headers, the compiler checks several places in this order:

For quoted includes (#include "file.h"):

• The same directory as the source file
• The project's include directories
• The system include directories

For angle bracket includes (#include <file.h>):

• The system include directories only

Most IDEs let you specify additional include directories. In Visual Studio:

1// Project structure:
2MyGame/
3  Source/
4    Player/
5      Player.cpp
6    Weapons/
7      Sword.h

If Player.cpp needs to include Sword.h, we have options:

1// Option 1: Relative path (fragile)
2#include "../Weapons/Sword.h"
3
4// Option 2: Add include directory
5#include "Sword.h" // Better!

In Visual Studio:

1. Right-click your project
2. Select Properties
3. Navigate to C/C++ General
4. Add your paths to Additional Include Directories

For example, adding $(ProjectDir)Source lets you include files from anywhere in the Source directory.

Here's a common way to organize files:

1MyGame/
2  Include/
3    Character.h
4    Weapon.h
5    Items/
6      Potion.h
7  Source/
8    Character.cpp
9    Weapon.cpp
10    Items/
11      Potion.cpp

With Include added to our include directories, we can write:

1// From Include/
2#include "Character.h"
3
4// From Include/Items/
5#include "Items/Potion.h"

This makes our includes cleaner and more maintainable, and lets us move files around without breaking includes.