#
# linear search for user-supplied word
# words in list can be in any order
# commands: s word -- search for word
#           a word -- add word to list
#           p   -- print the list
#
# Matt Bishop, MHI 289I, Fall 2019
#

# this is global just to emphasize how that works
wordlist = [ "when", "in", "the", "course", "of", "human", "events" ]

# search a list of words for a word (linear search)
# parameters: word, the word to find in the list
# returns: index (+1) of word in list
#          -1 if not in list
def search(word, wordlist):
        # go through the list a word at a time
        for i in range(len(wordlist)):
                # see if there is a match
                if wordlist[i] == word:
                        # yep! return position (success)
                        return i + 1
        # return that you found nothing
        return -1

# append words to a list
# parameters: none
# returns: nothing
def addword(word, wordlist):
        # use existing routine to see if this is a duplicate
        found = search(word, wordlist)
        if (found == -1):
                # nope -- add it
                wordlist.append(word)
                print("Added word '%s' to list" % word)
        else:   # yep -- say so
                print("'%s' is already in the list (word %d)" % (word, found))

# this puts it all together
def main():
        # declaration -- using the initial one
        global wordlist
        # loop; need a dummy non-empty string to go in
        instr = 'next'
        while len(instr) > 0:
                # read in word; quit on EOF
                try:
                        find = input("what do I do (s word, a word, p)? ")
                except EOFError:
                        return
                # nothing typed?
                if len(find) == 0:
                        return
                # find the word if it's there
                l = find.split()
                #
                # now process the word and command
                #
                # first, be sure it's of the right form
                if len(l) == 0:
                        pass
                elif len(l) > 2:
                        print("Your input can have only 2 words!")
                # s word -- find word in the list
                elif l[0] == 's':
                        # be sure it is of the right form
                        if len(l) == 1:
                                print("s: what should I search for?")
                        else:
                                # look for the word in the list
                                found = search(l[1], wordlist)
                                # announce result
                                if found == -1:
                                        print("'%s' is not in the list" % l[1])
                                else:
                                        print("'%s' is word number %d" % (l[1], found))
                # a word -- append word to list
                elif l[0] == 'a':
                        # be sure it is of the right form
                        if len(l) == 1:
                                print("a: what should I add?")
                        else:
                                addword(l[1], wordlist)
                # p -- print list
                elif l[0] == 'p':
                        for i in range(len(wordlist)):
                                print("%2d. %s" % (i+1, wordlist[i]))
                # you got me -- unknown command, so say so
                else:
                        print("Unknown command '%s'" % find)
                        
#
# and away we go!
#
main()