You can write 1&#x27;000&#x27;000 for a million in C++14. <a href="http:&#x2F;&#x2F;en.cppreference.com&#x2F;w&#x2F;cpp&#x2F;language&#x2F;integer_literal" rel="nofollow">http:&#x2F;&#x2F;en.cppreference.com&#x2F;w&#x2F;cpp&#x2F;language&#x2F;integer_literal</a>.<p>They didn&#x27;t use underscores because <i>_100_000</i> is a valid identifier in C&#x2F;C++.<p>Arbitrary bases aren&#x27;t there.