//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){ //Jika Button ditekan
 nyalaLED++; //Data variabel nyalaLED +1
 delay(100); //Tunda waktu 100 ms
 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);
 }
}