relay - task -3 arduino

int relay = 7;
char data;
// replay - task -2
void setup() {
  pinMode(relay, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if(Serial.available()>0){
  // data available

  data = Serial.read();

  if(data=='a'){
    digitalWrite(relay, HIGH);
    Serial.println("Relay ON");
  }
  else if(data=='b'){
    digitalWrite(relay, LOW);
    Serial.println("Relay OFF");
  }
  }

}