and <code>A</code> through <code>F</code> represent values 10 through 15.
</p>

<p>
For readability, an underscore character <code>_</code> may appear after
a base prefix or between successive digits; such underscores do not change
the literal's value.
</p>
<pre class="ebnf">
int_lit        = decimal_lit | binary_lit | octal_lit | hex_lit .