''subsubsection''-level headers not numbered by default

Question

I am a new user of latex. The command \subsection is working i.e. it shows me that this heading is subheading of previous heading with number like 1.1. But \subsubsection is not showing any number, I suppose it should show number like 1.1.1 . but it does not show at all any number.

What could be the issue?

Answer 1

I'm guessing that your document class is either report, book, scrreprt, or scrbook -- or a document class that's based on one of these four classes. These document classes have the following setting in common:

\setcounter{secnumdepth}{2}

It implies that level-0 (chapter), level-1 (section), and level-2 (subsection) headings are numbered by default, whereas level-3 (subsubsection) headings and higher-level headings (e.g., paragraph and subparagraph) are not numbered.

If you want level-3 headings to be numbered as well, you need to issue the following instruction in the preamble:

\setcounter{secnumdepth}{3}

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Aside: the article and scrartcl document classes, which do not feature level-0 (chapter) headers, have the following setting in common: \setcounter{secnumdepth}{3}. For the memoir document class, which provides level(-2) [!] headers, the default setting is \setcounter{secnumdepth}{1}.

Answer 2

Note that if you set:

\setcounter{secnumdepth}{4}

any occurrence of \paragraph will also be numbered. If you also want to appear these numbered sections in your table of contents, do:

\setcounter{tocdepth}{4}