int timer = 100;  //delay time for blinking

int ledPin;

int sw = 11;  

int a;    // variable to set the ouput pin
void setup()
{
  Serial.begin(9600);
  //loop to initialize the pin mode of digital pins 2 to 7
  pinMode(sw, INPUT);
  while (ledPin < 8)
  {
    pinMode (ledPin, OUTPUT);
    ++ledPin;
  } // end loop
} // end of setup()

void loop()
{
  while(Serial.available())
  {}
  a=Serial.parseInt();
  Serial.print(a);
  //for loop to blink from pin 2 through to pin 7 with a delay time mentioned in timer
  if (digitalRead(sw) == 1)
  {
    ledPin = 7;
    while (ledPin >= 2)
    {
      digitalWrite (ledPin, HIGH);
      delay (timer);
      digitalWrite (ledPin, LOW);
      Serial.println(ledPin);
      --ledPin;
    }// end of for loop

    //for loop to blink from pin 7 through to pin 2 with a delay time mentioned in timer
    ledPin = 2;
    while (ledPin < 7)
    {
      digitalWrite (ledPin, HIGH);
      delay (timer);
      digitalWrite (ledPin, LOW);
      ++ledPin;
    } // end for loop
  }
  else if(digitalRead(sw) == 0)
  {
    ledPin = 7;
    while (ledPin >= 2)
    {
      
      digitalWrite (ledPin, LOW);
      --ledPin;
    }
  }
} // end program