controlling of led using Bluetooth through string compare

 controlling of led using Bluetooth and Arduino through string compare 

code Arduino program

String data;

void root(String );
void setup()
{
  pinMode(13,OUTPUT);
  digitalWrite(13,LOW);
  Serial.begin(9600);
 
}
void loop()
{
  root(data);
  if(Serial.available())
  {
    data=Serial.readString();
    Serial.println(data);
    if(data== '4')
    digitalWrite(13,HIGH);
    else
    digitalWrite(13,LOW);
   
  }
}

void root(String data1)
{
  String str="mystringname";
if(Serial.available())
{
  String data1=Serial.readString();
 // Serial.write(data1);
  Serial.println(data1);
  if(data1==str)
  {
    digitalWrite(13,HIGH);
  }
    else
   {
    digitalWrite(13,LOW);
  }
}
}

OUTPUT

13 th led will high when you enter my stringname