Rock Paper Scissors

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.9", override: true},
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"}
])

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Create The Perfect AI

You’re going to create the perfect AI for rock paper scissors that will always win.

flowchart LR
scissors --beats--> paper --beats--> rock --beats--> scissors

Generate a random player choice of :rock ,:paper, or :scissors or manually enter :rock, :paper, and :scissors to determine your program works correctly.

player_choice = Enum.random([:rock, :paper, :scissors])

Then, return the winning choice of either :rock, :paper, or :scissors that beats the player’s choice.

Example solution

  player_choice = :scissors
  
  case player_choice do
    :rock -> :paper
    :paper -> :scissors
    :scissors -> :rock
  end

Enter your solution below.

player_choice = Enum.random([:rock, :paper, :scissors])
computer_choice = 
  case player_choice do
    :rock -> :paper
    :paper -> :scissors
    :scissors -> :rock
  end
IO.puts("You played #{player_choice}, I played #{computer_choice}.\nI win!")

Create Two Player Rock Paper Scissors

Now that you know how to create a rock paper scissors AI, you’re going to create a two player game of rock paper scissors.

Bind a player1_choice and player2_choice variable to :rock, :paper, or :scissors.

• If player1_choice beats player2_choice, return "Player 1 wins!".

• If player2_choice beats player1_choice, return "Player 2 wins!".

• If both players have the same choice, then return "Draw".

  Example solution

  player1 = :rock
  player2 = :scissors
  
  case {player1, player2} do
    {:rock, :scissors} -> "Player 1 Wins!"
    {:paper, :rock} -> "Player 1 Wins!"
    {:scissors, :paper} -> "Player 1 Wins!"
    {:rock, :paper} -> "Player 2 Wins!"
    {:paper, :scissors} -> "Player 2 Wins!"
    {:scissors, :rock} -> "Player 2 Wins!"
    {_same, _same} -> "Draw"
  end

  You can also reduce code repetition using functions and the in keyword to check if the value exists in a list.

  player1 = :rock
  player2 = :scissors
  
  beats? = fn choice1, choice2 ->
    {choice1, choice2} in [{:rock, :scissors}, {:paper, :rock}, {:scissors, :paper}]
  end
  
  cond do
    beats?.(player1, player2) -> "Player1"
    beats?.(player2, player1) -> "Player2"
    player1 == player2 -> "Draw"
  end

Enter your solution below.

player1 = Enum.random([:rock, :paper, :scissors])
player2 = Enum.random([:rock, :paper, :scissors])

check_win = fn p1, p2 -> 
  case {p1, p2} do
    {:rock, :scissors} -> true
    {:scissors, :paper} -> true
    {:paper, :rock} -> true
    _ -> false
  end
end

atos = &Atom.to_string(&1) |> String.capitalize

cond do
  check_win.(player1, player2) == true -> "#{atos.(player1)} beats #{player2}. Player 1 Wins!"
  check_win.(player2, player1) == true -> "#{atos.(player2)} beats #{player1}. Player 2 Wins!"
  true -> "#{atos.(player1)} times 2! It's a tie."
end

Commit Your Progress

DockYard Academy now recommends you use the latest Release rather than forking or cloning our repository.

Run git status to ensure there are no undesirable changes. Then run the following in your command line from the curriculum folder to commit your progress.

$ git add .
$ git commit -m "finish Rock Paper Scissors exercise"
$ git push

We’re proud to offer our open-source curriculum free of charge for anyone to learn from at their own pace.

We also offer a paid course where you can learn from an instructor alongside a cohort of your peers. We will accept applications for the June-August 2023 cohort soon.

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