These oparators perform a mathematical operation on a variable with another constant or variable. These operators are just a convenient shorthand:
x += y; // equivalent to the expression x = x + y;
x -= y; // equivalent to the expression x = x - y;
x *= y; // equivalent to the expression x = x * y;
x /= y; // equivalent to the expression x = x / y;
Here is an example:
int x = 2;
int y = 10;
x += 4; // x now contains 6
x -= 3; // x now contains 3
x *= y; // x now contains 30
x /= 2; // x now contains 15
x += max(20, 6); // x now contains 35
x -= sq(5); // x now contains 15
x: a numeric variable
y: a numeric variable, number constant, or any other expression that evaluates to a number (e.g. call to a function that returns a number).
License and Attribution
Portions of this page were adapted from the Arduino Reference Documentation, which is released under a Creative Commons Attribution-ShareAlike 3.0 License.