void setup() {
  // put your setup code here, to run once:
  //Q.2 write a program to interface LEDs on pin 
  //no. 10,11,12,13,blink alternatively at the delay of 1 sec.
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(13, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(10, HIGH);
  delay(1000);
  digitalWrite(10, LOW);
  delay(0);
  digitalWrite(11, HIGH);
  delay(1000);
  digitalWrite(11, LOW);
  delay(000);
  digitalWrite(12, HIGH);
  delay(1000);
  digitalWrite(12, LOW);
  delay(000);
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
  delay(000);



}