#define led 5
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600); 
pinMode(led,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
          int data=Serial.read(); 
          switch (data){
          case '0':
                digitalWrite(led,LOW);
                break;      

           case '1':
                digitalWrite(led,HIGH); 
                break;
                 
          case '2':
         blink();
          
                   
}
}

void blink(){
   for(int x=0; x<5; x++){
   digitalWrite(led,LOW);
   delay(500);
   digitalWrite(led,HIGH);
   delay(500);
   digitalWrite(led,LOW);
}
}