rock_paper_scissors.livemd

Rock Paper Scissors

Mix.install([
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"},
  {:tested_cell, github: "brooklinjazz/tested_cell"},
  {:utils, path: "#{__DIR__}/../utils"}
])

Navigation

Return Home Report An Issue

Setup

Ensure you type the ea keyboard shortcut to evaluate all Elixir cells before starting. Alternatively you can evaluate the Elixir cells as you read.

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

Loading

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.

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.

Commit Your Progress

Run the following in your command line from the beta_curriculum folder to track and save your progress in a Git commit.

$ git add .
$ git commit -m "finish rock paper scissors exercise"

Up Next

Previous	Next
Naming Numbers	Modules