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.. _arduino-modulo:

% (modulo)
==========

Description
-----------

Calculates the remainder when one integer is divided by another. It
is useful for keeping a variable within a particular range (e.g.
the size of an array).



Syntax
------

result = dividend % divisor



Parameters
----------

dividend: the number to be divided



divisor: the number to divide by



Returns
-------

the remainder



Examples
--------

::

    x = 7 % 5;   // x now contains 2
    x = 9 % 5;   // x now contains 4
    x = 5 % 5;   // x now contains 0
    x = 4 % 5;   // x now contains 4



Example Code
------------

::

    /* update one value in an array each time through a loop */
    
    int values[10];
    int i = 0;
    
    void setup() {}
    
    void loop()
    {
      values[i] = analogRead(0);
      i = (i + 1) % 10;   // modulo operator rolls over variable  
    }



Tip
---

The modulo operator does not work on floats.



See also
--------


-  `division <http://arduino.cc/en/Reference/Arithmetic>`_