reference/Modulo.html

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<p class='vspace'></p><h2>% (modulo)</h2>
<h4>Description</h4>
<p>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).
</p>
<p class='vspace'></p><h4>Syntax</h4>
<p>result = dividend % divisor
</p>
<p class='vspace'></p><h4>Parameters</h4>
<p>dividend: the number to be divided
</p>
<p class='vspace'></p><p>divisor: the number to divide by
</p>
<p class='vspace'></p><h4>Returns</h4>
<p>the remainder
</p>
<p class='vspace'></p><h4>Examples</h4>
<pre>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

</pre>
<p class='vspace'></p><h4>Example Code</h4>
<pre>
/* update one value in an array each time through a loop */

int values[10];
int i = 0;

void setup() {}

void loop()
{
  values[i] = analogRead(A0);
  i = (i + 1) % 10;   // modulo operator rolls over variable  
}

</pre>
<p class='vspace'></p><h4>Tip</h4>
<p>The modulo operator does not work on floats.
</p>
<p class='vspace'></p><h4>See also</h4>
<ul><li><a class='wikilink' href='Arithmetic.html'>division</a>
</li></ul><p class='vspace'></p><p><a class='wikilink' href='index.html'>Reference Home</a>
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<p class='vspace'></p><p><em>Corrections, suggestions, and new documentation should be posted to the <a class='urllink' href='http://forum.43oh.com/forum/28-energia/' rel='nofollow'>Forum</a>.</em>
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<p class='vspace'></p><p>The text of the Energia Reference is licensed under a
<a class='urllink' href='http://creativecommons.org/licenses/by-sa/3.0/' rel='nofollow'>Creative Commons Attribution-ShareAlike 3.0 License</a>.  Energia reference is based on Arduino reference.  Code samples in the reference are released into the public domain.
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