Arduino 7 - double-click

void setup() {
  pinMode(3, INPUT);
  Serial.begin(9600);
}

void loop() {
  if (digitalRead(3))
  {
    while (digitalRead(3) == 1) { }
    delay(50);
    long cas1 = millis();
    int double_click = 0;
    while (millis() < cas1 + 400) 
    {
      if (digitalRead(3) == 1)
        double_click = 1; 
    }     
    if (double_click == 1) Serial.println("double-click");
    else Serial.println("click");
    delay(200);
  }
}