Arduino Power control for turning on an arduino with a press button and power off with a continuous press

Arduino push button power control.ino

#define POWERCONTROL 2
#define POWERBUTTON  9
#define PULSETIME 3000

void setup() {
  // put your setup code here, to run once:
  pinMode(POWERCONTROL, OUTPUT);
  digitalWrite(POWERCONTROL, HIGH);
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);
  pinMode(POWERBUTTON, INPUT);
  digitalWrite(POWERBUTTON, LOW);
}

void check_power()
{
  static long timer = 0;

  if (digitalRead(POWERBUTTON))
  {
    if (timer == 0)
      timer = millis();
    if (timer + PULSETIME <= millis())
    {
      digitalWrite(POWERCONTROL, LOW);
      digitalWrite(13, LOW);
    }
  }
  else
    timer = 0;
  
}

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

  delay(100);
}