\chapter{\texttt{iostream} Headers}

\section{Keyboard Input and Screen Output}

\section{File In/Output}

\section{Header Files}
\begin{enumerate}
\item Header File: A file that allows the reusage of certain portions of source
    code. Header files are included to a source code via \imc{#include}, which
    inserts the header file code at that specific location.
\item Headers are used for declaring functions, classes, et cetra, and since a
    header file can be used multiple times by multiple source codes, defining
    variables and classes must not happen in a header file.
\item Include Guards: Since a single header file can be included multiple times
    throughout a compiling process and cause compilation errors, prevention
    methods are supported by the compilers. This ``guard from inclusion"s are
    called \textbf{Include guard}s: \imb{\cpp/03_iosheader.hpp}
\end{enumerate}
