diff options
Diffstat (limited to 'docs/source/lang/cpp/long.rst')
-rw-r--r-- | docs/source/lang/cpp/long.rst | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/docs/source/lang/cpp/long.rst b/docs/source/lang/cpp/long.rst new file mode 100644 index 0000000..d8498c0 --- /dev/null +++ b/docs/source/lang/cpp/long.rst @@ -0,0 +1,52 @@ +.. highlight:: cpp + +.. _lang-long: + +``long`` +======== + +The ``long`` data type stores extended size integer values. You can +use a ``long`` when your values are too large to fit into an :ref:`int +<lang-int>`. A ``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`` 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`` it is subject to the same :ref:`overflow issues +<lang-variables-rollover>` as any numeric data type. + +Here's an example of declaring a long (see :ref:`integer constants +<lang-constants-integers-u-l>` for an explanation of the "L" at the end of the +number):: + + // Speed of light in nanometers per second (approximate). + long c = 299792458000000000L; + +The general syntax for declaring an ``long`` variable named ``var``, +then giving it value ``val``, looks like:: + + long var = val; + +This is identical to the ``int`` syntax, with ``long`` replacing +``int``. + +Note that ``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`` instead of an ``int`` (besides the +extra storage) is that :ref:`arithmetic <lang-arithmetic>` operations +on ``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 <lang-unsignedlong>` +- :ref:`Integer Constants <lang-constants-integers>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt |