const int led = 7;
const int button = 8;

void setup() {
  pinMode(led, OUTPUT);
  pinMode(button, INPUT);
}

void loop() {
  if (digitalRead(button) == HIGH) {
    digitalWrite(led, HIGH);
    delay(200);
    digitalWrite(led, LOW);
    delay(200); 
  } else {                    
    digitalWrite(led, LOW);
  }
}