[CODE] Arduino 4 BIT LED binary counter

Here’s my “Hello World” on Arduino.
A 4-bit binary counter for arduino.
If you add another LED on the 5th pin, then it can count from 0 to 31 (32 values)

Circuit wired by @KataySantos

int counter = -1;
int MAX_VALUE = 16;

void updateLED(int pin, int bit, int ctr) {
  digitalWrite(pin, (ctr & (1<<bit)) == (1<<bit) ? HIGH : LOW);
}
void setup() {
  // this runs once
  pinMode(1, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
}

void loop() {
  // this runs repeatedly
  counter = (counter + 1) % MAX_VALUE;
  updateLED(1, 0, counter);
  updateLED(2, 1, counter);
  updateLED(3, 2, counter);
  updateLED(4, 3, counter);
  delay(500);
}