//Deklarasi variabel
const int LED1=9;
const int LED2=10;
const int LED3=11;
const int btnPin=2;

int btnData=0;
int nyalaLED=0;

void setup()
{
  //mengatur pin I/O
  pinMode (btnPin,INPUT);
  pinMode (LED1,OUTPUT);
  pinMode (LED2,OUTPUT);
  pinMode (LED3,OUTPUT);
}

void loop ()
{
  //Baca Data Button/Tombol
    btnData=digitalRead (btnPin);
    if (btnData==LOW) { 
      nyalaLED++;
      delay(100);
      if (nyalaLED>3) {nyalaLED=0;}
    }

    //pilihan penyalaan LED
    //Saat kondisi nyalaLED==0
    if (nyalaLED==0) {
      digitalWrite (LED1, LOW);
      digitalWrite (LED2, LOW);
      digitalWrite (LED3, LOW);
    }
    //Saat kondisi nyalaLED==1
    else if (nyalaLED==1) {
      digitalWrite (LED1, HIGH);
      digitalWrite (LED2, LOW);
      digitalWrite (LED3, LOW);
    }

    //Saat kondisi nyalaLED==2
    else if (nyalaLED==2) {
      digitalWrite (LED1, HIGH);
      digitalWrite (LED2, HIGH);
      digitalWrite (LED3, LOW);
    }
    //Saat kondisi nyalaLED==3
    else if (nyalaLED==3){
    digitalWrite (LED1, HIGH);
    digitalWrite (LED2, HIGH);
    digitalWrite (LED3, HIGH);
    }

}