Your assignment should be submitted in a single Word doc (.doc or .docx). It should include your scenario diagram for Problem 1, and your Ruby source code for Problems 2 and 3. Contact me or post to our discussion board if you have any questions concerning this assignment. Note that, per the course syllabus, no submission will be accepted past the due date.

This assignment asks you to use scenario diagrams to think about the interactions between objects, and explores Ruby a bit further.

Problem 1:

Here is an interaction in a tic-tac-toe game, with user input in bold:

>> gm = Game.new('andy', 'mike')
=> #
>> gm.play_game('mike')
Mike, enter your next O move (1-9): 1
O - -
- - -
- - -
Andy, enter your next X move (1-9): 3
O - X
- - -
- - -
Mike, enter your next O move (1-9): 5
O - X
- O -
- - -
Andy, enter your next X move (1-9): 3
Bad move dude! You go again. O - X
- O -
- - -
Andy, enter your next X move (1-9): 6
O - X
- O X
- - -
Mike, enter your next O move (1-9): 9
O - X
- O X
- - O
Mike, you won!
=> nil
>> gm.play_game('karen')
I don't know that player. Please try again.
=> nil

>> gm.play_game('andy')
Andy, enter your next O move (1-9): 5
- - -
- O -
- - -

When a new game is created, two players register with it by name (the arguments to Game.new). The play_game message is called with one of the player's names and starts a new game where that player plays first using the O marker. (A game can be sent repeated play_game messages so the same pair of players can play multiple games). In each iteration, the current player is prompted for the position of her move and then she enters the move number, where the nine squares are numbered in row-major order from 1 through 9. If a move is illegal (i.e., already occupied), the current player is scolded and prompted again for a move. After each move, the board is redrawn. A game ends when either one of the players forms a horizontal, vertical, or diagonal row of her three markers (in the usual way), or the board is full indicating a tie.

The assignment is not to implement this game in Ruby. Rather, the assignment is to use scenario diagrams to discover the objects, their responsibilities, and the messages they respond to.

Specifically, focus on the scenario of a typical iteration: If the current game is not over, the current player is prompted for a legal move which she supplies and then the move is made and the current game board is displayed. Hand in a single scenario diagram that you believe represents your best design. You can use whatever tools you want to create this diagram including the online tool at https://www.websequencediagrams.com/ which I use for my scenario diagrams.

Problem 2

A DNA strand is represented by a string of the characters A, C, G, and T, each of which represents a nucleotide. Each nucleotide has its complement as indicated by this Ruby hash:

NUCLEOTIDE_COMPLEMENT = {
'A' => 'T', 'T' => 'A', 'C' => 'G', 'G' => 'C'
}

The reverse-complement of a DNA string is a new string in which each nucleotide is replaced by its complement and the string is reversed. Reverse-complements are important in bioinformatics since a strand of DNA can be read in forward direction or, equivalently, its complementary strand can be read in its forward direction, which is reverse of the original string's direction. Add the reverse_complement method to your DNA class. In response to reverse_complement, it returns a new DNA instance representing its reverse-complement. Note also that a == b if and only if DNA instances a and b represent the same DNA strand.

>> dna1 = DNA.new('ATTGCC')
=> ATTGCC
>> dna2 = dna1.reverse_complement
=> GGCAAT
>> dna2
=> GGCAAT
>> dna1
=> ATTGCC
>> dna2.reverse_complement
=> ATTGCC
>> dna1.reverse_complement.reverse_complement == dna1
=> true

Problem 3

Write a PhoneContact class that gets initialized with a phone number and a label. The phone number should follow one of the formats of the Phone class from the previous assignment (and you should use the Phone class in this assignment). A label is either a symbol or a string. A phone contact responds to the label, phone_number, and to_s messages. Note that phone_number returns a Phone object:

>> contact1 = PhoneContact.new('(954) 555-1212', :work)
=> (954) 555-1212 (work)
>> contact1.label
=> "work"
>> contact1.phone_number
=> "(954) 555-1212"
>> contact1.to_s
=> "(954) 555-1212 (work)"
>> contact2 = PhoneContact.new(' 955-555-1212', "cell")
=> (955) 555-1212 (cell)
>> contact2.phone_number.area_code
=> 955