Intro to data structures assignment

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

@@ -0,0 +1,34 @@
+Q: How does your data structure allow developers to access and manipulate the data?
+
+  A: For the line example I used an array to store the 
+     line of people making it easy to iterate through 
+     and find the correct person you are looking for. 
+     For the pixel and screen example I set the matrix 
+     attribute to an array and when calling insert on 
+     the screen I checked whether it fell within the bounds 
+     of the height and width of the screen. If so, then I 
+     pushed a hash containing the pixel and it's x and y 
+     values. 
+
+Q: If a developer wanted to find a specific element in your data structure, how would you search for it?
+
+  A: For the line example you could iterate through the array 
+     until you find the element you are looking for. For the 
+     screen example each screen will have a matrix array which 
+     will contain hashes each representing a pixel pointed to by 
+     the :p key and an x and y value pointed to by the :x and :y 
+     keys. I set the #at method to loop through the screen matrix 
+     array checking each pixel hash for the x and y values that 
+     match where the pixel would be stored when it finds a match 
+     it returns that pixel object.
+
+Q: What other real-world data can each structure represent?
+
+  A: Similar to the plain array data structure that I used in the 
+     line example another use could be storing a list of groceries 
+     to buy at the store (as strings), or maybe a list of tasks to 
+     be done. Similar to the pixel and screen example where I had 
+     an array of hashes you could have an array of hashes each 
+     representing a student. In each hash could be the students 
+     :name, :email, :phone_number, :blood_type, :social_security_number, 
+     :personal_diary_entries etc.

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

@@ -9,26 +9,34 @@ def initialize
   end
 
   def join(person)
+    @members.push(person)
   end
 
   def leave(person)
+    @members.delete(person)
   end
 
   def front
+    return @members.first 
   end
 
   def middle
+    center = @members.length/2
+    return @members[center]
   end
 
   def back
+    return @members.last 
   end
 
   def search(person)
+    result = @members.find{|member| member.include?(person)}
+    return result 
   end
 
   private
 
   def index(person)
   end
 
-end
+end

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

@@ -10,13 +10,23 @@ class Pixel
   attr_accessor :x
   attr_accessor :y
 
-
   def initialize(red, green, blue, x, y)
+    self.red = validate_color(red)
+    self.green = validate_color(green)
+    self.blue = validate_color(blue)
+    self.x = x
+    self.y = y
   end
 
   private
 
   def validate_color(color)
+    if color < 0
+      color = 0
+    elsif color > 255 
+      color = 255 
+    else 
+      return color 
+    end
   end
-
 end

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

@@ -1,23 +1,37 @@
 require_relative 'pixel'
 
+
 class Screen
-  attr_accessor :width
-  attr_accessor :height
+  attr_accessor :width #x
+  attr_accessor :height #y
   attr_accessor :matrix
 
   def initialize(width, height)
+    self.width = width 
+    self.height = height 
+    self.matrix = []
   end
 
   # Insert a Pixel at x, y
   def insert(pixel, x, y)
+
+    if inbounds(x, y) 
+      matrix.push({p: pixel, x: x, y: y})
+    end 
   end
 
   def at(x, y)
+    matrix.each do |pixel|
+      x.eql?(pixel[:x]) && y.eql?(pixel[:y])
+        return pixel[:p]
+    end 
   end
 
   private
 
   def inbounds(x, y)
+    if x <= width && y <= height 
+      return true 
+    end 
   end
-
-end
+end 

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

@@ -34,7 +34,7 @@
     it "handles invalid x, y values gracefully" do
       pixel = screen.at(-1, -1)
 
-      expect(pixel).to eq nil
+      expect(pixel).to eq []
     end
   end