This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.
The modulo operator (%) returns the remainder of a number divided by another. As in this example, it is often used to keep numerical values within a set range.
int num = 0;
num = (num + 1) % 10;