The following code typically loops one more time than times e.g. with 0, it loops once, with 1, it loops twice.

#define PTIME 30 void pulse(int pin, int times) { do { digitalWrite(pin, HIGH); delay(PTIME); digitalWrite(pin, LOW); delay(PTIME); } while (times--); } 

ADDITIONAL SUGGESTION#1: Decide whether it should loop 0 times or once, when times is set to 0; looping almost forever is probably not desired.
ADDITIONAL SUGGESTION#2: Add optional additional parameter int duration that defaults to PTIME or 30.