Hepl me thanks Compilation error: incomplete type 'std::string' {aka 'std::__cxx11::basic_string<char>'} used in nested name specifier

[truonggiang38]

Compilation error: incomplete type 'std::string' {aka 'std::__cxx11::basic_string'} used in nested name specifier

[UKHeliBob]

Welcome to the forum

Please do not post pictures of code and/or error messages

Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'

Use code tags (the < CODE/ > icon above the compose window) to make it easier to read and copy for examination

https://forum.arduino.cc/t/how-to-get-the-best-out-of-this-forum

In my experience this is the easiest way to tidy up the code and add the code tags

Start by tidying up your code by using Tools/Auto Format in the IDE to make it easier to read. Then use Edit/Copy for Forum and paste what was copied in a new reply. Code tags will have been added to the code to make it easy to read in the forum thus making it easier to provide help.

[J-M-L]

+1 on please never ever again posting pictures of text...

for your issue replace std::string::npos with just -1

[truonggiang38]

yes