// Using Array + Buttons to turn on and off 4 LEDs
const int buttonPins[] = {2, 3, 4, 5};  
const int ledPins[] = {8, 9, 10, 11};   
bool ledState[] = {false, false, false, false};  

void setup() {
  
  for (int i = 0; i < 4; i++) {
    pinMode(ledPins[i], OUTPUT);
    pinMode(buttonPins[i], INPUT_PULLUP);
  }
}

void loop() {
 
  for (int i = 0; i < 4; i++) {
    if (digitalRead(buttonPins[i]) == LOW) {  
      delay(200);  
      ledState[i] = !ledState[i];  
      digitalWrite(ledPins[i], ledState[i]);  
    }
  }
}