[USMA:54851] Abbreviation for Degrees Celsius

[c...@traditio.com]

I'm sure that this has been addressed before, but I can find no specific 
answer in my library of standards documents.  When using the limited ASCII 
character set, how do you write the symbol for the degree Celsius?  Is it 
40 oC, using the rule that there is to be a space between the numeral and 
the symbol.  Or is it 40oC, as one commonly sees it in print?