Cannot convert 'String' to 'uint8_t {aka unsigned char}' in initialization

Question

Hey all I am trying to convert a string into a uint8_t with the following code:

String data = "#255101987";
String tmp1 = data.substring(1, 3);
uint8_t first = (String)tmp1;

I am getting the error of:

cannot convert 'String' to 'uint8_t {aka unsigned char}' in initialization

Any help would be great as I thought adding (String) in front of the varible would solve the issue but it hasn't as you can tell.

• Ignacio Vazquez-Abrams: Do you want the ASCII value of the character or do you want to parse the string contents as a number?
• Nick Gammon: I presume from the substring call s/he expects to find 255 in the variable.
• StealthRT: @NickGammon is correct. I am looking for the 255 within the string and needing to convert that to the uint8_t.

Answer 1

uint8_t first = atoi (tmp1.substring(1, 3).c_str ()); 

Or even:

String data = "#255101987";
uint8_t first = atoi (data.substring(1, 3).c_str ()); 

• StealthRT: That worked great. Thanks for the help, Nick!