play BULL & COW

Instructions:
Computer assumes 4 digit number
(no repeat digit),
you have to guess it

as you guess,
computer suggests how close you are
by identifying
COW for every digit guessed right,
but at wrong place
BULL for every digit guessed right
alongwith its place.

for example -
if number is 1234 and guess is 1928
you have 1 BULL for digit 1
and 1 COW for digit 2

So go ahead and guess what I have assumed