Binary search

print """This program will try to determine a number you have randomly chosen from 1 to 100 through binary search.
Please use 'y' for Yes, 'h' for Higher and 'l' for Lower."""

def query(lb, ub, turns_taken):
    guess = (int) (lb+ub) / 2
    q = raw_input("Is your number %d? " % guess)
    if q == 'y':
        use_plural = "" if turns_taken == 1 else "s"
        print "Yeah, got it in %d turn%s!" % (turns_taken, use_plural)
    elif q == 'h':
        query(guess, ub, turns_taken + 1)
    elif q == 'l':
        query(lb, guess, turns_taken + 1)
    else: #Invalid answer
        raise ValueError("Please enter 'y' for Yes, 'h' for Higher and 'l' for Lower.")

query(1, 100, 1)