#define BUTTON  11
#define LED     12

int led_status = 0;

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

void loop() {

  if(button_status(BUTTON))
  {
    if(!led_status)
    {
      led_status = 1;
      digitalWrite(LED,HIGH);
    }
    else{
      led_status = 0;
      digitalWrite(LED,LOW);
    }
  }
  // put your main code here, to run repeatedly:

}

int button_status(int gpio)
{
  int status = 0;
  unsigned long t = millis();

  while(digitalRead(gpio))
  {
    if((millis() - t) > 20)
    {
      status = 1;
    }
  }
  return status;
}