bool x, state; // Declaration 
void setup(){
  pinMode(4, OUTPUT); // Declaring output pin 
  pinMode(16, INPUT); // Declaring input pin 
  state = true; // Initialization 
}

void loop(){
  while(1){
    x = digitalRead(16); // Assignning value
    if(x == HIGH){
      digitalWrite(4, HIGH);
      delay(500);
    }
  }
}