void setup() {
  // put your setup code here, to run once:

  pinMode(12, OUTPUT);
  pinMode(3, INPUT_PULLUP);
  Serial.begin(9600);

}

void loop() {
  // put your main code here, to run repeatedly:

  int x = digitalRead(3);
  if(x==0){
    digitalWrite(12, HIGH);
    Serial.println("Switch ON , LED ON");
  }else{
    digitalWrite(12, LOW);
    Serial.println("Switch OFF , LED OFF");
  }

}