/**
 * Increment Decrement. 
 * by BARRAGAN <http://barraganstudio.com> 
 * 
 * Writing "a++" is equivalent to "a = a + 1".  
 * Writing "a--" is equivalent to "a = a - 1".   
 */

int current = 0;  // variable the keeps which light must be turn on next 

void setup() { 
  for(int i=0; i<8; i++) {  // set pins 0-7 as outputs 
    pinMode(i, OUTPUT);  
  } 
} 

void loop() { 
  turn_all_off();  // turns all LEDs off 
  digitalWrite(current, HIGH);  // set the current light ON 
  delay(200);  // wait for 200ms 
  current++;  // increment current LED 
  if(current > 7) {  // range check, if last LED goes back to LED 0 
    current = 0; 
  } 
}

void turn_all_off() {  // function to turn off all the LEDs            
  for(int i=0; i<8; i++) {  // connected to digital pins 0-7
    digitalWrite(i, LOW); 
  } 
} 


