-and-variable-declarations.html"><a href="scalar-data-types-and-variable-declarations.html#declaring-optional-variables"><i class="fa fa-check"></i>Declaring optional variables</a></li>
</ul></li>
<li class="chapter" data-level="5.5" data-path="vector-and-matrix-data-types.html"><a href="vector-and-matrix-data-types.html"><i class="fa fa-check"></i><b>5.5</b> Vector and matrix data types</a>
<ul>
<li class="chapter" data-level="" data-path="vector-and-matrix-data-types.html"><a href="vector-and-matrix-data-