// LED Pins (YOUR WIRING)
const int greenLED = 8;   // Green LED on pin 8
const int yellowLED = 7;  // Yellow LED on pin 7
const int redLED = 9;     // Red LED on pin 9

// Button Pins (YOUR WIRING)
const int btnRed = 2;     // Red button → State 2
const int btnGreen = 3;   // Green button → State 0
const int btnYellow = 4;  // Yellow button → State 1

int state = 0;

void setup() {

  // LED outputs
  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);

  // Buttons with internal pullup
  pinMode(btnRed, INPUT_PULLUP);
  pinMode(btnGreen, INPUT_PULLUP);
  pinMode(btnYellow, INPUT_PULLUP);
}

void loop() {

  // Read buttons (pressed = LOW)
  if (!digitalRead(btnGreen)) {
    state = 0;   // Green state
  }
  else if (!digitalRead(btnYellow)) {
    state = 1;   // Yellow state
  }
  else if (!digitalRead(btnRed)) {
    state = 2;   // Red state
  }

  // Apply states
  switch(state) {

    case 0:   // GREEN ON
      digitalWrite(greenLED, HIGH);
      digitalWrite(yellowLED, LOW);
      digitalWrite(redLED, LOW);
      break;

    case 1:   // YELLOW ON
      digitalWrite(greenLED, LOW);
      digitalWrite(yellowLED, HIGH);
      digitalWrite(redLED, LOW);
      break;

    case 2:   // RED ON
      digitalWrite(greenLED, LOW);
      digitalWrite(yellowLED, LOW);
      digitalWrite(redLED, HIGH);
      break;
  }
}