Remainder operation 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). The % (percent) symbol is used to carry out remainder operation.
remainder = dividend % divisor;remainder : variable. Allowed data types: int, float, double
dividend : variable or constant. Allowed data types: int
divisor : non zero variable or constant. Allowed data types: int
int x = 0;
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
x = -4 % 5; // x now contains -4
x = 4 % -5; // x now contains 4/* 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; // remainder operator rolls over variable
}The remainder operator does not work on floats.
If the first operand is negative, the result is negative (or zero).
Therefore, the result of x % 10 will not always be between 0 and 9 if x can be negative.
Corrections, suggestions, and new documentation are very welcomed. They can be contributed to the energia website repository on Github.
The text of the Energia getting started and reference guides are licensed under a Creative Commons Attribution-ShareAlike 3.0 License. The Energia reference is based on the Wiring/Arduino reference. Code samples in the guide are released into the public domain.
Energia sketches are C/C++ based and compiled with the open-source compiler MSPGCC or arm-gcc-none-eabi. The Energia language comes from Wiring. The Energia environment is based on Processing and includes modifications made by Wiring and Arduino.
© Energia