Coding Help Starting and Ending with a certain Character

youeyg96:
This is the full code with example 3 from Robin2 integrated into it

You have added a huge amount of code into my recvWithStartEndMarkers() function. Don't do that. Leave my function unchanged and put your code in its own function and call it from loop() whenever newData == true. Something like this

void loop() {
    recvWithStartEndMarkers();
    if (newData == true) {
       doMyStuff();
       newData = false;
    }
}

If you ensure that each function just has a single purpose it is easy to test each of them separately. See Planning and Implementing a Program

...R