const int ledPin = 13;
const int btnPin = 2;


int ledState = LOW;
int btnState = HIGH;

void setup() {

pinMode(ledPin, OUTPUT);
pinMode(btnPin, INPUT_PULLUP);
digitalWrite(ledPin, ledState);
}

void loop() {
  
  if (digitalRead(btnPin) == LOW)
  {
    if (btnState != LOW)
    {
      ledState = !ledState;
      digitalWrite(ledPin, ledState);
    }
    btnState = LOW;
  }
  else
  {
    btnState = HIGH;
  }
delay(100);
}