Who wrote closer by chainsmokers and halsey?

Closer was written by Halsey, Shaun Frank, Isaac Slade, and Joe King

Explanation:

c, d, e, f, g, a, b, and c.

sometimes western music will also use solfege. the names of these are do ra me fa sol la si (or ti) and do.

to indicate a note a half step higher or lower then the original note, you would say c # (for a half a step above c) or bb (for half a step below b)