Wait for input message before entering void loop

Question

How can I wait for an input message in arduino code before the sketch starts void loop

I've tried using while (!Serial.available())

void setup(void)
{
  //SD Card
  Serial.begin(9600);
   //Wait for input from C# app
   Serial.flush();
   while(!Serial.available())
   {
    Reader = Serial.readString();
    if(Reader = "Start")
    {
      break;
    }
   }
}

I would like to pause the code until the message "Start" is received.

Answer 1

You can do something like this to wait until you receive "Start".

void setup(void)
{
    //SD Card
    Serial.begin(9600);
    //Wait for input from C# app
    Serial.flush();

    while(!Reader.equals("Start"))
    {
        Reader = Serial.readString();
        Reader.trim();
    }
}