// variable holding the button state 
int buttonState; 
 
// variable holding previous button state 
int previousButtonState = LOW; 
 
// variable holding the LED state 
int ledState = HIGH; 
 
int buttonPin = 2; 
const int ledPin = 13; 
 
// millis always stored in long 
// becomes too big for int after 32,767 millis or around 32 seconds 
 
// timestamp of a previous bounce 
long previousDebounceTime = 0; 
 
// debounce time in millis, if the LED is still quirky increase this value 
long debounceDelay = 50; 
 
void setup() { 
  pinMode(buttonPin, INPUT); 
  pinMode(ledPin, OUTPUT); 
} 
 
void loop() { 
  // for now it's the same as in previous example 
  int reading = digitalRead(buttonPin);  
   
  // if the previous reading is different than the previous button state   
  if (reading != previousButtonState) { 
    // we'lll reset the debounce timer 
    previousDebounceTime = millis(); 
  }  
   
  // if the reading is the same over a period of debounceDelay 
  if ((millis() - previousDebounceTime) > debounceDelay) { 
    // check if the button state is changed 
    if (reading != buttonState) { 
      buttonState = reading; 
       
      // toggle the LED state only when the button is pushed 
      if (buttonState == HIGH) { 
        ledState = !ledState; 
      } 
    } 
  } 
   
  // set the LED: 
  digitalWrite(ledPin, ledState); 
   
  // save current reading so that we can compare in the next loop 
  previousButtonState = reading; 
}