problem with " const float " (arduino's guide)

hi, i started using arduino a few days ago. i'm trying to do the examples of the prodjects' book, but i can' t fix a code: i am doing the prodject n. 3 and it says "error " in the line 2(const float baselineTemp = 20.0; ) this is the copy of the official book's command. how can i fix it?? please help me! :sweat_smile:

Post all of your code. In Code tags.

d_killer: and it says "error "

That's all it said? That's unusual. Usually the compiler gives you a long run of output and usually for an error it tells you exactly what it was upset about. Why don't you post the actual error message? There is probably more information in that. Even if you don't understand it, chances are that someone here will.

problem fixed: it was my pc, it hasn' t updated the command. it was a previous error. thanks for help