Arduino Code

int ledPin = 13;
int swPin = 8;
boolean X0 = LOW;
boolean X1 = HIGH;
boolean flagg = LOW;

void setup() {
  // put your setup code here, to run once:
  pinMode(ledPin, OUTPUT);
  pinMode(swPin, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  X1=digitalRead(swPin);
  if ((X0 == LOW) && (X1==HIGH)) {
    flagg = !flagg;
  }
  X0=X1;
  digitalWrite(ledPin, flagg);
  }