// Define pins for LEDs
const int ledPins[] = {8, 9, 10, 11};   // LED pins

void setup() {
  // Initialize the LEDs and start Serial communication
  Serial.begin(9600);
  for (int i = 0; i < 4; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // Check if data has been sent through Serial
  if (Serial.available() > 0) {
    char input = Serial.read();  // Read user input
    controlLED(input);  // Pass the input to control the LEDs
  }
}

// Function to control LEDs based on user input
void controlLED(char input) {
  switch (input) {
    case '1':
      digitalWrite(ledPins[0], HIGH);  // Turn on LED 1
      break;
    case '2':
      digitalWrite(ledPins[1], HIGH);  // Turn on LED 2
      break;
    case '3':
      digitalWrite(ledPins[2], HIGH);  // Turn on LED 3
      break;
    case '4':
      digitalWrite(ledPins[3], HIGH);  // Turn on LED 4
      break;
    case '0':
      for (int i = 0; i < 4; i++) {
        digitalWrite(ledPins[i], LOW);  // Turn off all LEDs
      }
      break;
    default:
      Serial.println("Invalid input. Use 1-4 to turn on LEDs, 0 to turn off.");
      break;
  }
}