const int buttonPin = 2;     // the number of the pushbutton pin
const int ledPin =  13;      // the number of the LED pin
boolean ledOn = LOW;
// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
  Serial.begin(9600);
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
}
void loop() {
  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);
  Serial.println(buttonState);
  // check if the pushbutton is pressed.
  // if it is, the buttonState is HIGH:
  if (buttonState == HIGH ) {
    if (ledOn == LOW) {
      // turn LED on:
      digitalWrite(ledPin, HIGH);
      ledOn = !ledOn; // put the Led status to 1
    }
    else {
      // turn LED off:
      digitalWrite(ledPin, LOW);
      ledOn = !ledOn;
    }
    delay(300);// wait to avoid conflict
  }
}