======% (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   ====
<code arduino>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
</code>

====Example Code   ====
<code arduino>
/* 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  
}
</code>

====Tip   ====
The modulo operator does not work on floats.

====See also   ====

* [[ Arithmetic | division]]


Source: arduino.cc