Code from arduino class.

arduino_course.c

// Communication is done by ansci 
const int FIRST_ON = '0';
const int SECOND_ON = '1';
const int ALL_ON = '2';
const int ALL_OFF = '3';

boolean stop = false;

struct led{
  int delayLength;
  int pinNumber;
  int numberOfLoop;
};

void setup() {

  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  
//  Serial.begin(9600); 
}

void loop() {

  struct led myLed;
  myLed.delayLength = 1000;
  myLed.pinNumber = 4;
  myLed.numberOfLoop = 3;
  
  blinkFor(myLed);
}

void serialListen(void) {
    if (Serial.available() > 0) {
      Serial.print("\nready\n");
      int input = Serial.read();
      Serial.write("read :");
      Serial.write(input);
      Serial.write("\n");
      
      if (input == FIRST_ON){
        Serial.print("first on");
        turnLightOff(5);
         blinkLight(4);
      }
      else if (input == SECOND_ON) {
        Serial.print("second on");
        turnLightOff(4);
        blinkLight(5);
      }
      else if (input == ALL_ON) {
        Serial.print("all on");
        blinkLight(4);
        blinkLight(5);
      }
      else {
        Serial.print(FIRST_ON);
        turnLightOff(4);
        turnLightOff(5);
      }
      
    } 
}

void blinkLight(int ledNO) {
  digitalWrite(ledNO, HIGH);
}

void turnLightOff(int ledNO) {
  digitalWrite(ledNO, LOW); 
}

void blinkFor(struct led myLed) {
  if (!stop){
    for (int i = 0; i < myLed.numberOfLoop; i++) {
      blinkLight(myLed.pinNumber);
      delay(myLed.delayLength);
      turnLightOff(myLed.pinNumber);
      delay(myLed.delayLength);
    }
    stop = true;
  }
}