Many hd44780 displays have a degree symbol in character position 0xdf or 223 decimal.
The glcd library uses fonts that are different from a hd44780 display.
To display a degree symbol as a character, you will need a font that contains
a degree symbol character.
I went and looked at all the fonts that are included with the library and none
of them have a degree symbol.
If you are using the System5x7 font and would like to add a degree symbol,
it is fairly easy.
You can add a degree symbol to System5x7 font table.
Here is the definition for the degree symbol:
0x00, 0x06, 0x09, 0x09, 0x06 // degree symbol
This can be added to the table by either replacing a character that you don't want/need
or it can be added to the back end of the table.
If this is added to the backend of the font table, you also have to bump
the character count from at the top of the table from 0x60 to 0x61.
If you add to the back end of the table you will use 0x80 or 128 decimal to print the character.
Attached is a SystemFont5x7.h header file that has the degree symbol added to the back end
of the font table.
Just keep in mind that if you use a modified version of the font, that your code will
only work properly with that modified font file. So that means that if you want/need
others to able to build your code you will need to also supply them with the modified