When trying to compile my project all previously working classes are flagging up as having errors. One of the errors is 'string not found' when in the class it is included.
#include <string>
I have tried changing the 'Compile source as' in the Build settings to Objective-C++ but this hasn't helped
Also gives an error when compiling about derived data.
I have managed to successfully compile the project with the "Legacy Build System" (by activating it under File->Project/Workspace Settings), so this confirms that this is a problem with the "New Build System" which is enabled by default in Xcode 10
EDIT: Make sure to remove all folders found in DerivedData, to do this go to Xcode->Preferences->Locations and open the external link to DerivedData folder. Then go back into Xcode and clean build and rebuild