From 964da7f52da37744f740d07f2be3ce05ac6e7db1 Mon Sep 17 00:00:00 2001
From: nahome <nahom.teshome@yahoo.com>
Date: Fri, 8 Jun 2018 23:18:18 -0700
Subject: [PATCH] Intro to data structures

---
 .../intro-answers.txt                         | 24 +++++++++++++++++++
 .../line/line.rb                              |  9 ++++++-
 .../screen/pixel.rb                           | 12 ++++++++++
 .../screen/screen.rb                          | 10 +++++++-
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/01-data-structures/01-introduction-to-data-structures/intro-answers.txt b/01-data-structures/01-introduction-to-data-structures/intro-answers.txt
index e69de29b..c8968fd9 100644
--- a/01-data-structures/01-introduction-to-data-structures/intro-answers.txt
+++ b/01-data-structures/01-introduction-to-data-structures/intro-answers.txt
@@ -0,0 +1,24 @@
+1. A line of people at an amusement park ride.
+
+  The data of the people in line is structured as an array,
+  so developers can access and manipulate the data using Array
+  manipulation techniques.
+
+  A developer can find a specific element by using the index
+  of the element.
+
+  This data structure can be used to organize the orders of
+  customers in a restaurant in a first comes first served basis.
+
+  2. Pixels on a computer screen
+
+  Pixels are created in three colors and validated so that the
+  color coordinate values are not out of boundary.After a pixel
+  is created it can be inserted to a specific coordinate on the
+  screen using two dimensional array. A pixels x and y coordinates
+  can't be negative or greater than the width and array.
+
+  A developer can access a pixel by using its width and array coordinates.
+
+  This data structure can be used to create a sitting arrangement for
+  different depending on peoples relationships, ranks or age.
diff --git a/01-data-structures/01-introduction-to-data-structures/line/line.rb b/01-data-structures/01-introduction-to-data-structures/line/line.rb
index 84bfe59e..eacbbc2d 100644
--- a/01-data-structures/01-introduction-to-data-structures/line/line.rb
+++ b/01-data-structures/01-introduction-to-data-structures/line/line.rb
@@ -9,26 +9,33 @@ def initialize
   end
 
   def join(person)
+    self.members.push(person)
   end
 
   def leave(person)
+    self.members.slice!(self.members.index(person))
   end
 
   def front
+    self.members.first
   end
 
   def middle
+    self.members[()(members.length/2).ciel)]
   end
 
   def back
+    self.members.last
   end
 
   def search(person)
+    self.members.include?(person) ? person : nil;
   end
 
   private
 
   def index(person)
+    self.members.index(person)
   end
 
-end
\ No newline at end of file
+end
diff --git a/01-data-structures/01-introduction-to-data-structures/screen/pixel.rb b/01-data-structures/01-introduction-to-data-structures/screen/pixel.rb
index e286557e..83ef51cb 100644
--- a/01-data-structures/01-introduction-to-data-structures/screen/pixel.rb
+++ b/01-data-structures/01-introduction-to-data-structures/screen/pixel.rb
@@ -12,11 +12,23 @@ class Pixel
 
 
   def initialize(red, green, blue, x, y)
+    @red = validate_color(red)
+    @green = validate_color(green)
+    @blue = validate_color(blue)
+    @x = x
+    @y = y
   end
 
   private
 
   def validate_color(color)
+    if color > 255
+      return color = 255
+    elsif color < 0
+      return color = 0
+    else
+      return color
+    end
   end
 
 end
diff --git a/01-data-structures/01-introduction-to-data-structures/screen/screen.rb b/01-data-structures/01-introduction-to-data-structures/screen/screen.rb
index 8a0aee67..7ede073a 100644
--- a/01-data-structures/01-introduction-to-data-structures/screen/screen.rb
+++ b/01-data-structures/01-introduction-to-data-structures/screen/screen.rb
@@ -6,18 +6,26 @@ class Screen
   attr_accessor :matrix
 
   def initialize(width, height)
+    @width = width
+    @height = height
+    @matrix = Array.new(width) { Array.new(height) }
   end
 
   # Insert a Pixel at x, y
   def insert(pixel, x, y)
+    @matrix[x][y] = pixel
   end
 
   def at(x, y)
+    return @matrix[x][y]
   end
 
   private
 
   def inbounds(x, y)
+    if (x < 0 || x > width) || (y < 0 || y > height)
+      pixel = nil
+
   end
 
-end
\ No newline at end of file
+end