Button Changes the Color of the LED

int buttonPin = 2;     // the number of the pushbutton pin
int ledPin =  11;      // the number of the LED pin
int buttonState = 0;         // variable for reading the pushbutton status

void setup()
{
  // 디지털출력핀 초기회
  for(int pin=11 ; pin<=13 ; pin++)
  {
    pinMode(pin, OUTPUT);
  }
  
  // 디지털입력핀 초기화
  pinMode(buttonPin, INPUT);
}

void loop()
{
  buttonState = digitalRead(buttonPin);

  if(buttonState == LOW)
  {
    ledPin++;

    if(ledPin > 13)
    {
      ledPin = 11;
    }
  }
  
  digitalWrite(ledPin, HIGH);   // LED 켜기
  delay(500);                   // 0.5초 기다리기
  digitalWrite(ledPin, LOW);    // LED 끄기
  delay(500);                   // 0.5초 기다리기
}