// const int buttonPin = 2;  // the pin that the pushbutton is attached to
// const int ledPin = 13;    // the pin that the LED is attached to

// // Variables will change:
// int buttonPushCounter = 0;  // counter for the number of button presses
// int buttonState = 0;        // current state of the button
// int lastButtonState = 0;    // previous state of the button

// void setup() {
//   // initialize the button pin as a input:
//   pinMode(buttonPin, INPUT);
//   // initialize the LED as an output:
//   pinMode(ledPin, OUTPUT);
//   // initialize serial communication:
//   Serial.begin(9600);
// }


// void loop() {
//   // read the pushbutton input pin:
//   buttonState = digitalRead(buttonPin);

//   // compare the buttonState to its previous state
//   if (buttonState != lastButtonState) {
//     // if the state has changed, increment the counter
//     if (buttonState == HIGH) {
//       // if the current state is HIGH then the button went from off to on:
//       buttonPushCounter++;
//       Serial.println("on");
//       Serial.print("number of button pushes: ");
//       Serial.println(buttonPushCounter);
//     } else {
//       // if the current state is LOW then the button went from on to off:
//       Serial.println("off");
//     }
//     // Delay a little bit to avoid bouncing
//     delay(50);
//   }
//   // save the current state as the last state, for next time through the loop
//   lastButtonState = buttonState;


//   // turns on the LED every four button pushes by checking the modulo of the
//   // button push counter. the modulo function gives you the remainder of the
//   // division of two numbers:
//   if (buttonPushCounter % 4 == 0) {
//     digitalWrite(ledPin, HIGH);
//   } else {
//     digitalWrite(ledPin, LOW);
//   }
// }









/*
 * Created by ArduinoGetStarted.com
 *
 * This example code is in the public domain
 *
 * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-button-debounce
 */

// constants won't change. They're used here to set pin numbers:
// const int BUTTON_PIN = 2;        // the number of the pushbutton pin
// const int ledPin = 13;
// const int DEBOUNCE_DELAY = 50;   // the debounce time; increase if the output flickers

// // Variables will change:
// int lastSteadyState = LOW;       // the previous steady state from the input pin
// int lastFlickerableState = LOW;  // the previous flickerable state from the input pin
// int currentState;                // the current reading from the input pin

// // the following variables are unsigned longs because the time, measured in
// // milliseconds, will quickly become a bigger number than can be stored in an int.
// unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled

// void setup() {
//   // initialize serial communication at 9600 bits per second:
//   Serial.begin(9600);
//   // initialize the pushbutton pin as an pull-up input
//   // the pull-up input pin will be HIGH when the switch is open and LOW when the switch is closed.
//   pinMode(BUTTON_PIN, INPUT_PULLUP);
//   pinMode(ledPin, OUTPUT);
// }

// void loop() {
//   // read the state of the switch/button:
//   currentState = digitalRead(BUTTON_PIN);

//   // check to see if you just pressed the button
//   // (i.e. the input went from LOW to HIGH), and you've waited long enough
//   // since the last press to ignore any noise:

//   // If the switch/button changed, due to noise or pressing:
//   if (currentState != lastFlickerableState) {
//     // reset the debouncing timer
//     lastDebounceTime = millis();
//     // save the the last flickerable state
//     lastFlickerableState = currentState;
//   }

//   if ((millis() - lastDebounceTime) > DEBOUNCE_DELAY) {
//     // whatever the reading is at, it's been there for longer than the debounce
//     // delay, so take it as the actual current state:

//     // if the button state has changed:
//     if (lastSteadyState == HIGH && currentState == LOW)
//     {
//       Serial.println("The button is pressed");
//       digitalWrite(ledPin, HIGH);
//     }
//     else
//     digitalWrite(ledPin, LOW);
//     // else if (lastSteadyState == LOW && currentState == HIGH)
//     // {
//     //   Serial.println("The button is released");
//     //   digitalWrite(ledPin, LOW);
//     // }

//     // save the the last steady state
//     lastSteadyState = currentState;
//   }
// }





















// constants won't change. They're used here to set pin numbers:
// const int BUTTON_PIN = 2;        // the number of the pushbutton pin
// const int ledPin = 13;
// const int DEBOUNCE_DELAY = 50;   // the debounce time; increase if the output flickers

// const int AnalogPin = A0;

// // Variables will change:
// int lastSteadyState = LOW;       // the previous steady state from the input pin
// int lastFlickerableState = LOW;  // the previous flickerable state from the input pin
// int currentState;                // the current reading from the input pin

// // the following variables are unsigned longs because the time, measured in
// // milliseconds, will quickly become a bigger number than can be stored in an int.
// unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled

// void setup() {
//   // initialize serial communication at 9600 bits per second:
//   Serial.begin(9600);
//   // initialize the pushbutton pin as an pull-up input
//   // the pull-up input pin will be HIGH when the switch is open and LOW when the switch is closed.
//   pinMode(BUTTON_PIN, INPUT_PULLUP);
//   pinMode(ledPin, OUTPUT);
// }

// void loop() {
//   // read the state of the switch/button:
//   // currentState = digitalRead(BUTTON_PIN);
//   currentState = analogRead(AnalogPin);

//   // check to see if you just pressed the button
//   // (i.e. the input went from LOW to HIGH), and you've waited long enough
//   // since the last press to ignore any noise:

//   // If the switch/button changed, due to noise or pressing:
//   if (currentState != lastFlickerableState) {
//     // reset the debouncing timer
//     lastDebounceTime = millis();
//     // save the the last flickerable state
//     lastFlickerableState = currentState;
//   }

//   if ((millis() - lastDebounceTime) > DEBOUNCE_DELAY) {
//     // whatever the reading is at, it's been there for longer than the debounce
//     // delay, so take it as the actual current state:

//     // if the button state has changed:
//     if (lastSteadyState == HIGH && currentState == LOW)
//     {
//       Serial.println("The button is pressed");
//       digitalWrite(ledPin, HIGH);
//     }
//     // else
//     // digitalWrite(ledPin, LOW);
//     // else if (lastSteadyState == LOW && currentState == HIGH)
//     // {
//     //   Serial.println("The button is released");
//     //   digitalWrite(ledPin, LOW);
//     // }

//     // save the the last steady state
//     lastSteadyState = currentState;
//   }
// }
















const int buttonPin = 2;  // the number of the pushbutton pin
const int ledPin = 13;    // the number of the LED pin

// Variables will change:
int ledState = HIGH;        // the current state of the output pin
int buttonState;            // the current reading from the input pin
int lastButtonState = LOW;  // the previous reading from the input pin

// the following variables are unsigned longs because the time, measured in
// milliseconds, will quickly become a bigger number than can be stored in an int.
unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
unsigned long debounceDelay = 50;    // the debounce time; increase if the output flickers

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);

  // set initial LED state
  digitalWrite(ledPin, ledState);
}

void loop() {
  // read the state of the switch into a local variable:
  int reading = digitalRead(buttonPin);

  // check to see if you just pressed the button
  // (i.e. the input went from LOW to HIGH), and you've waited long enough
  // since the last press to ignore any noise:

  // If the switch changed, due to noise or pressing:
  if (reading != lastButtonState) {
    // reset the debouncing timer
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    // whatever the reading is at, it's been there for longer than the debounce
    // delay, so take it as the actual current state:

    // if the button state has changed:
    if (reading != buttonState) {
      buttonState = reading;

      // only toggle the LED if the new button state is HIGH
      if (buttonState == HIGH) {
        ledState = !ledState;
      }
    }
  }

  // set the LED:
  digitalWrite(ledPin, ledState);

  // save the reading. Next time through the loop, it'll be the lastButtonState:
  lastButtonState = reading;
}