.. highlight:: cpp

.. _arduino-else:

if/else
=======

``if``/\ ``else`` allows greater control over the flow of code than
the basic :ref:`if <arduino-if>` statement, by allowing multiple tests
to be grouped together. For example, an :ref:`analog input
<arduino-analogread>` could be tested, with one action taken if the
input was less than 500, and another action taken if the input was 500
or greater. The code would look like this::

    if (pinFiveInput < 500) {
      // action A
    } else {
      // action B
    }

``else`` can precede another ``if`` test, so that multiple, mutually
exclusive tests can be run at the same time.

Each test will proceed to the next one until a true test is
encountered. When a true test is found, its associated block of code
is run, and the program then skips to the line following the entire
if/else construction. If no test proves to be true, the default
``else`` block is executed, if one is present, and sets the default
behavior.


Note that an ``else if`` block may be used with or without a
terminating ``else`` block, and vice-versa. An unlimited number of
such ``else if`` branches is allowed.  Here is a code example::

    if (pinFiveInput < 500) {
      // do Thing A
    } else if (pinFiveInput >= 1000) {
      // do Thing B
    } else {
      // do Thing C
    }

Another way to express branching, mutually exclusive tests, is with a
:ref:`switch/case <arduino-switchcase>` statement.

See Also
--------

- :ref:`if <arduino-if>`
- :ref:`switch/case <arduino-switchcase>`