int currentState =  0, previousState = 0;
int btnPin = 10, ledPin = 12;


void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
pinMode(btnPin, INPUT_PULLUP);
pinMode(ledPin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
int currentState = digitalRead(btnPin);
if (currentState == 1 && previousState == 0) {
  int ledPinVal = digitalRead(ledPin);
  if (ledPinVal == 1) {
    digitalWrite(ledPin, 0);
  }
 if (ledPinVal == 0) {
    digitalWrite(ledPin, 1);
  }
}
//for debugging purpose
  Serial.print("currentState: "); Serial.print(currentState);
  Serial.print("; previousState: "); Serial.println(previousState);
  previousState = currentState;
}


//Lesson on Debouncing

//Assignment:

//Use a sensor in place of the button such that if the sensor senses a presence, the light will come on and vice versa.