Serial Integer Convert Issue

Using Arduino Programming Questions
1

Hey there, looking to get a second opinion on the following code:

unsigned long serialdata;
int inbyte;

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  if (Serial.available()){
    getSerial();
  }
}

long getSerial()
{
  serialdata = 0;
  while (inbyte != '/')
  {
    inbyte = Serial.read();  
    if (inbyte > 0 && inbyte != '/')
    { 
      serialdata = serialdata * 10 + inbyte - '0';
    }
  }
  
  Serial.println(serialdata);
  return serialdata;
  inbyte = 0;
}

It prints the first serialdata value, but any value after that it prints 0. Have no idea why...

2

Well, let's see...suppose the incoming data is "123/"

long getSerial()
{
  serialdata = 0;
  while (inbyte != '/')
  {
    inbyte = Serial.read();  
    if (inbyte > 0 && inbyte != '/')
    { 
      serialdata = serialdata * 10 + inbyte - '0';
    }
  }
  
  Serial.println(serialdata);
  return serialdata;
  inbyte = 0;
}

On the first read, a '1' is read, so we find serialdata is 0, so we end up with ASCII 49 - ASCII 48 equals 1, so serialdata now equals 1. When the 2 comes in, we get 1 * 10 + 2 = 12. When the 3 comes in we get 12 * 10 + 3 = 123. The next byte is your termination character, so it appears that this is a convoluted replacement for atol().

BTW, the inbyte = 0 statement at the bottom is never executed and you could simplify the code by using Serial.readBytesUntil().

3 
  return serialdata;
  inbyte = 0;

What is the reason for the useless code after the return statement?