#define button_pin 16
#define led_pin 18
int button_state = 0;
void setup() 
{
pinMode(18, OUTPUT);
pinMode(button_pin , INPUT_PULLUP);
Serial.begin(115200);
}

void loop() 
{
  button_state=digitalRead(button_pin);
  if(button_state == LOW)
  {
    digitalWrite(18, HIGH);
    Serial.println("led on");
    delay(1000);
  }
  else
  {
  digitalWrite(18, LOW);
  Serial.println("led off");
delay(1000);
  }
}