Problems using atoi

Projects Programming
1

MacOS
Arduino IDE2.2.1
Arduino Uno WiFi rev 2
WiFiNINA 1.8.14
Arduino Motor Shield rev 3

for (int i = 0; i < STD_BUFFER_SIZE; ++i) {
  if (incomingData1[i].length() > 0) { // Check if the string is not empty
    localData1 = atoi(incomingData1[i].c_str());
    break; // Stop after converting the first non-empty string
  } //if (incomingData1[i].length() > 0)
} //for (int i = 0; i < STD_BUFFER_SIZE; ++i)

I'm using atoi() to change the incoming TCP/IP string to an int. When I run this code as part of a separate sketch, it compiles fine. When I compile the same code as part of a much larger sketch, I get;

error: request for member 'length' in 'incomingData1.arduino::String::operator[](((unsigned int)i))', which is of non-class type 'char'
if (incomingData1[i].length() > 0) { // Check if the string is not empty

Should I be doing the conversion in a different way?

2

You shouldn't be using Strings with atoi(). To check the length of a C-string (zero terminated character array), use strlen().

4

I spent all day converting to strings. I'll go back to an earlier array-based version.

There's more to learn I guess. My son the programmer says that if you know all about C++, you're wrong.

Thanks!

5

take the character at position "i" of the variable "incomingData1" and check how long = how many bytes long this single character is.

This makes no sense at all.

You are using the Arduino Uno WiFi rev 2
I don't know the details of the core-files of this arduino-board.

on ESP8266 / ESP32 you have a data-type IPAddress which is in fact an array of bytes where each byte holds one part of the IP-adress

So in fact you can't go wrong.
Never.
Because it would take you all time until the end of the universe to know "everything about C++"

best regards Stefan