# assumes list has been sorted before call
def binsearch_rec(list, target):
    return do_binsearch_rec(list, target, 0, len(list)-1)
    
def do_binsearch_rec(list, target, first, last):
    if last < first:
        ans = -1
    else:
        mid = (first + last)/2
        if target == list[mid]:
            ans = mid
        elif target < list[mid]:
            ans = do_binsearch_rec(list, target, first, mid-1)
        else:
            ans = do_binsearch_rec(list, target, mid+1, last)
    return ans

def binsearch(list, target):
    ans = -1
    first = 0
    last = len(list)-1
    while last >= first:
        mid = (first + last)/2
        if target == list[mid]:
            ans = mid
            break
        elif target < list[mid]:
            last = mid-1
        else:
            first = mid+1
    return ans

def main():
    while True:
        list = raw_input("Enter a list (or q to quit): ")
        if list == 'q':  break
        list = eval(list)
        list.sort()
        print "sorted list is: ", list
        while True:
            key = raw_input(" Search key (or q to get next list): ")
            if key == 'q': break
            key = eval(key)
            print " recursive result is:     ", binsearch_rec(list, key)
            print " non-recursive result is: ", binsearch(list, key)

    print 'Program quits.'


main()