\r is the
C-style
escaped (
backwhacked)
character known as
carriage return (correctly noted by
mingux as being
ASCII 0x0d = 13). On many
terminals, this returns the
cursor to the first
cell of the current
line. But this is by no means
standard; there is no generally standard behaviour for
\r and
\n, especially not on
hard copy terminals.
What C does guarantee is that whatever \r is, it will be a single character.