Does putchar reads single letter or digit also is printf is printing ASCII code here

Question

does getchar reads only one digit or letter
https://code.sololearn.com/cqpRAB60Z36r/?ref=app

Answer 1

Yes
https://code.sololearn.com/c4bmL1TtD0nM/?ref=app

Answer 2

putchar writes one letter to stdout

Answer 3

And yes, printf prints ascii