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.. highlight:: cpp
.. _lang-longlong:
``long long``
=============
The ``long long`` data type stores extended size integer values. You
can use a ``long long`` when your values are too large to fit into an
:ref:`int <lang-int>`. A ``long long`` occupies 8 bytes of memory.
This yields a range of approximately -9.2×10^18 to 9.2×10^18 (that's
9.2 billion billion, or about 92 million times the number of stars in
the Milky Way galaxy). The exact range of a ``long long`` on the
Maple is from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807,
or -2^63 to (2^63-1). A ``long long`` it is subject to the same
:ref:`overflow issues <lang-variables-rollover>` as any numeric data
type.
A synonym for the ``long long`` type is ``int64``.
Here's an example of declaring a long long (see :ref:`integer
constants <lang-constants-integers-u-l>` for an explanation of the
"LL" at the end of the number)::
// Speed of light in nanometers per second (approximate).
long long c = 299792458000000000LL;
The general syntax for declaring an ``long long`` variable named ``var``,
then giving it value ``val``, looks like::
long long var = val;
This is identical to the ``int`` syntax, with ``long long`` (or, at
your option, ``int64``) replacing ``int``.
Note that ``long long`` values will still :ref:`overflow
<lang-int-overflow>`, just like ``int`` values, but their much larger
range makes this less likely to happen.
The downside to using a ``long long`` instead of an ``int`` (besides
the extra storage) is that :ref:`arithmetic <lang-arithmetic>`
operations on ``long long``\ s will take slightly longer than on
``int``\ s.
See Also
--------
- :ref:`char <lang-char>`
- :ref:`unsigned char <lang-unsignedchar>`
- :ref:`int <lang-int>`
- :ref:`unsigned int <lang-unsignedint>`
- :ref:`unsigned long long <lang-unsignedlonglong>`
- :ref:`Integer Constants <lang-constants-integers>`
- :ref:`Variables <lang-variables>`
.. include:: /arduino-cc-attribution.txt
|
