Header Files

Files ending with .h or .hpp. These files allow us to save C++ Forward Declaration in one file so we can import them in other files. You Require the source file with the actual C++ code with this file. grades.h is paired with grades.cpp Implicitly compiled. No need to change your compilation command in command line.

Writing Header Files

You need:

1. Header Guard
2. All the C++ Forward Declaration of the original C++ file that we want other files to see

Good convention

• Dont write functions or variables inside header files! It breaks C++ ODR during link-time
• Source files should always #include their header file
• Do not #include .cpp files. again C++ ODR

Standard Library Header Files

These are header files we have not written and are located at include directories, defaulting to the directory the IDE or compiler have declared.

• You #include with <> to denote this location.
• You can optionally leave the .h in the file name

List of std namespace header files

• iostream.h
• cstdlib
• iomanip
• cstdint

Transitive includes

Implicit #includes that header files have to include other header files, per sake for dependencies.

Header Only FIles

a type of header file that does not have an associated c++ program. these are the best ones for they have the most ammount of reusability. You will be using Inline Functions a lot