const int led_1 = 2;
const int led_2 = 3;
const int led_3 = 4;
const int led_4 = 5;

const int push_button1 = 8;
const int push_button2 = 9;
const int push_button3 = 10;
const int push_button4 = 11;

void setup () {
  pinMode (2, OUTPUT);
  pinMode (3, OUTPUT);
  pinMode (4, OUTPUT);
  pinMode (5, OUTPUT);

  pinMode (8, INPUT);
  pinMode (9, INPUT);
  pinMode (10, INPUT);
  pinMode (11, INPUT);

  Serial.begin(9600);
}

  int nilai_pb1;
  int nilai_pb2;
  int nilai_pb3;
  int nilai_pb4;

void loop(){
  nilai_pb1 = digitalRead(8);
  nilai_pb2 = digitalRead(9);
  nilai_pb3 = digitalRead(10);
  nilai_pb4 = digitalRead(11);
 
  Serial.print("pb1=");
  Serial.print (nilai_pb1); Serial.print("\t");

  Serial.print("pb2=");
  Serial.print (nilai_pb2); Serial.print("\t");

  Serial.print("pb3=");
  Serial.print (nilai_pb3); Serial.print("\t");

  Serial.print("pb4=");
  Serial.print (nilai_pb4); Serial.print("\n");

  delay(200);

  if(nilai_pb1 == 1){
    digitalWrite (led_1, HIGH); 
  }
  else{
    digitalWrite (led_1, LOW);
  }

  if(nilai_pb2 == 1){
    digitalWrite (led_2, HIGH);
  }
  else{
    digitalWrite (led_2, LOW);
  }

  if(nilai_pb3 == 1){
    digitalWrite (led_3, HIGH);
  }
  else{
    digitalWrite (led_3, LOW);
  }

  if(nilai_pb4 == 1){
    digitalWrite (led_4, HIGH);
  }
  else{
    digitalWrite (led_4, LOW);
  }
}