Why am I receiving this error: “expected unqualified-id before numeric constant”?
You're using an invalid variable name (1cd starts with the number 1).


Variables can consist of both uppercase (A-Z) and lowercase(a-z)
letters.
Variables can contain numbers 0 to 9, but cannot start with a number.
Variables may not have the same names as Arduino language keywords,
e.g. you cannot have a variable named float.
If you try and save a sketch with a space in the file name, the IDE will change the space to an underscore.