month represents a month of a year
. It normally holds values in the range 1 to 12,
but may hold non-negative values outside this range
. It can be constructed with any
unsigned value,
which will be subsequently truncated to fit into
month's unspecified internal storage
. month meets the
Cpp17EqualityComparable (Table
28)
and
Cpp17LessThanComparable (Table
29) requirements,
and participates in basic arithmetic with
months objects,
which represent a difference between two
month objects
.