Which input method is fastest?

[govind_lahoti]

Hello all,
I needed some help on input methods in C and C++.
Can someone please tell me which of the following input method is fastest:
scanf()
gethchar()
getchar_unlocked()
getc()
getc_unlocked()
fread()
gets()
getline()
cin.get()

Thanks in advance

[daft_wullie]

And this discussion is not sufficient?