int button = 7;
int led = 4;
int button_state = 0;
void setup() {
  // put your setup code here, to run once:
  pinMode(button, INPUT);
  pinMode(led, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  button_state = digitalRead(button);
  if (button_state == HIGH) {
    digitalWrite(led, HIGH);
    delay(100);
    digitalWrite(led, LOW);
  }
  else {
    digitalWrite(led, LOW);
  }
}