// Define constants for pin numbers
const int redLedPin = 12;
const int yellowLedPin = 7;
const int greenLedPin = 2;

// Define constants for timing
const int redDuration = 5000;  // 5000 milliseconds (5 seconds) for red light
const int yellowDuration = 2000;  // 2000 milliseconds (2 seconds) for yellow light
const int greenDuration = 5000;  // 5000 milliseconds (5 seconds) for green light

void setup() {
  // Set the LED pins as outputs
  pinMode(redLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);

  // Initial default state for the traffic light
  trafficLightDefault();
}

void loop() {
  // Traffic light sequence
  redLight();
  yellowLight();
  greenLight();
}

void trafficLightDefault() {
  // Default state: Red light on, others off
  digitalWrite(redLedPin, HIGH);
  digitalWrite(yellowLedPin, LOW);
  digitalWrite(greenLedPin, LOW);
  delay(redDuration);
}

void redLight() {
  // Red light on, others off
  digitalWrite(redLedPin, HIGH);
  digitalWrite(yellowLedPin, LOW);
  digitalWrite(greenLedPin, LOW);
  delay(redDuration);
}

void yellowLight() {
  // Yellow light on, others off
  digitalWrite(redLedPin, LOW);
  digitalWrite(yellowLedPin, HIGH);
  digitalWrite(greenLedPin, LOW);
  delay(yellowDuration);
}

void greenLight() {
  // Green light on, others off
  digitalWrite(redLedPin, LOW);
  digitalWrite(yellowLedPin, LOW);
  digitalWrite(greenLedPin, HIGH);
  delay(greenDuration);
}