Guide to LaTeX (4th Edition) (Tools and Techniques

182 Chapter 8. User Customizations
8.1.2 User-defined counters
The user may create new counters with the command
\newcounter{counter name}[in counter]
where counter name is the name of the newly established counter. This
may be any combination of letters that is not already the name of an
existing counter. Thus none of the names of the L AT E X counters listed
above may be used as counter name nor any name of a previously defined
user counter.
The optional argument in counter is the name of another counter
that already exists (L AT E X or user defined) and has the effect that the newly
defined counter is reset to zero whenever in counter is incremented by one
of the commands \stepcounter or \refstepcounter (see below). For
example, the subsection counter is reset to zero whenever the section
counter is incremented.
The \newcounter command may not appear in any file that is read in
with the \include command (Section 9.1.2). It is therefore best to put all
\newcounter commands into the preamble.
8.1.3 Changing counter values
Every counter, whether L AT E X or user defined, has an initial value of zero;
this can be altered with the following commands:
\setcounter{counter}{num}
This command is self-explanatory: the specified counter is assigned
the integer value num.
\addtocounter{counter}{num}
With this command, the value of the counter is increased by the
integer num, which may be positive or negative.
\stepcounter{counter}
The value of the counter is increased by one, and at the same
time all its sub-counters (that is, those that have this counter as
their in counter) are reset to zero (see above).
\refstepcounter{counter}
This command has the same effect as \stepcounter but also
makes counter the current counter for the cross-referencing command
\label (see Section 9.2.1).
This last command may be applied, for example, within the figure
or table environments when the \caption command is missing and yet
there is to be a reference in the text to the figure or table number using the
\ref command. Then \refstepcounter{figure} or \refstepcounter
{table} is given within that float environment to bring the corresponding