Completed assignment - intro to data structures

01-data-structures/01-introduction-to-data-structures/intro-answers.txt

@@ -0,0 +1,21 @@
+1. How does your data structure allow developers to access and manipulate the data?
+
+Both the line and screen data structures allow developers to access and manipulate data through arrays. Line is a simple array
+of strings which allows developers to easily add new strings to the end of the array using line.join(person), remove members
+using line.leave(person), or find a specific person in line using line.search(person). The screen data structure is a two-dimensional
+array which allows developers to model a screen by inserting pixels at specified x,y coordinates using screen.insert(x,y)
+or find the pixel at a specified coordinate using screen.at(x,y).
+
+2. If a developer wanted to find a specific element in your data structure, how would you search for it?
+
+Line allows developers to find a specific person using line.search(person) which utilizes the private method line.index(person).
+Line.index() returns the index of the string that was searched for and allows developers to return the string at that index in
+the line.members array. Screen uses screen.at(x,y) to find the pixel at the specified x,y coordinate. If the x,y coordinate
+provided is within the dimensions of the screen, screen.at() will return the pixel data.
+
+3. What other real-world data can each structure represent?
+
+The line data structure is analogous to a queue in online gaming. When a user sends a request to enter a game, they are placed in
+a queue. The queue is first in, first out and a user can cancel the request to join (line.leave()). The screen data structure
+could also represent a digital picture. A digital picture could also be modeled as a two-dimensional array with specific
+pixel information at specific coordinates. 

01-data-structures/01-introduction-to-data-structures/line/line.rb

@@ -9,26 +9,36 @@ def initialize
   end
 
   def join(person)
+    self.members.push(person)
   end
 
   def leave(person)
+    self.members.delete_at(index(person))
+    puts self.members
   end
 
   def front
+    self.members.first
   end
 
   def middle
+    index = (self.members.length/2).floor
+    self.members[index]
   end
 
   def back
+    self.members.last
   end
 
   def search(person)
+    person_index = index(person)
+    self.members[index(person)] if !person_index.nil?
   end
 
   private
 
   def index(person)
+    self.members.index { |p| p == person }
   end
 
-end
+end

01-data-structures/01-introduction-to-data-structures/screen/pixel.rb

@@ -12,11 +12,23 @@ class Pixel
 
 
   def initialize(red, green, blue, x, y)
+    self.red = validate_color(red)
+    self.blue = validate_color(blue)
+    self.green = validate_color(green)
+    self.x = x
+    self.y = y
   end
 
   private
 
   def validate_color(color)
+    if color < 0
+      color = 0
+    elsif color > 255
+      color = 255
+    else
+      color
+    end
   end
 
 end

01-data-structures/01-introduction-to-data-structures/screen/screen.rb

@@ -6,18 +6,30 @@ class Screen
   attr_accessor :matrix
 
   def initialize(width, height)
+    self.width = width
+    self.height = height
+    self.matrix = Array.new(self.width) { Array.new(self.height) }
   end
 
   # Insert a Pixel at x, y
   def insert(pixel, x, y)
+    valid_coordinate = inbounds(x,y)
+    self.matrix[x][y] = pixel if !valid_coordinate.nil?
   end
 
   def at(x, y)
+    valid_coordinate = inbounds(x,y)
+    self.matrix[x][y] if !valid_coordinate.nil?
   end
 
   private
 
   def inbounds(x, y)
+    if (x < self.width && x >= 0) && (y < self.height && y >= 0)
+      return x, y
+    else
+      nil
+    end
   end
 
-end
+end