I know, it is a little bit tricky to find out the right place of the headerfiles. I checked it again and again and did it compare with the other files included in the system.
I placed it in ardino0022/libraries at the same place, where the "normal" directories are.
I did compare the structure of the old and my new directories - it was no difference.
I did change the names of the directories and checked in the arduino-ide what happened - the ide did show the changed names at the right place.
At least did I change in the file, named by the error message, e.g. uint8_t in uint13_t, in order to check if is the right file. The error messages did show the new errors.
I'm sure (relatively) ardino has the right files to work with. I repaet the failure message and you can see, that the right file is named:
HelloWorld:4: error: cannot declare variable 'lcd' to be of abstract type 'LiquidCrystal_I2C'
C:\Progr-MCU\Arduino-0022\arduino-0022\libraries\LiquidCrystal_I2C_vArd10/LiquidCrystal_I2C.h:59: note: because the following virtual functions are pure within 'LiquidCrystal_I2C':
C:\Progr-MCU\Arduino-0022\arduino-0022\hardware\arduino\cores\arduino/Print.h:40: note: virtual void Print::write(uint8_t)
I'm afraid, there is an other problem.
But it seems to be not to big (so I hope). The ide shows in the sketch only one line marked:
LiquidCrystal_I2C lcd(0x27,16,2); // set the LCD address to 0x27 for a 16 chars and 2 line display
and below it is to read:
cannot declare variale 'lcd' to be of abstract type 'LiquidCrystal_I2C'.
I hope the information is enough so you can find out the raison of my problem.