created new shuffle program to extend Array class; added orange tree script

Author: StevenXL

ToDo.txt

@@ -1,5 +1,4 @@
 1 - Chapter 9: Modern Roman Numerals
 7 - Chapter 11 --> What is the difference between mixed up and random?
-8 - Chapter 12: Section 12.6
 9 - Chapter 13: Orange Tree
 10 - Chapter 13: Interactive Baby Dragon 

chapter_10_recursion/shuffle.original

@@ -0,0 +1,23 @@
+# the point of this exercise is to create a method that takes an array and
+# returns the items in the array in in a completely random way
+# 
+# for this program, I am going to be using the rand function, which returns an
+# integer greater than or equal to 0 but less than the number passed. 
+#
+# I'm also going to use the Array#delete_at(index) function, which deletes the
+# element at the given index, but also returns it
+
+def shuffle(input)
+    randomized = Array.new
+
+    until input.length == 0
+        # initialize a random integer within the array's # of elements
+        randomized_index = rand(input.length)
+
+        # push the element at that integer to our output array and delete that
+        # element from our input array
+        randomized << input.delete_at(randomized_index)
+    end
+
+    return randomized
+end

chapter_10_recursion/shuffle.rb

@@ -6,18 +6,25 @@
 #
 # I'm also going to use the Array#delete_at(index) function, which deletes the
 # element at the given index, but also returns it
+#
+# In this method, we are extending the Array class to support our shuffle
+# method. Notice the use of the keyword self to refer to the calling object
 
-def shuffle(input)
-    randomized = Array.new
+class Array
+    def shuffle
+        original_array = Array.new(self)
 
-    until input.length == 0
-        # initialize a random integer within the array's # of elements
-        randomized_index = rand(input.length)
+        randomized = Array.new
 
-        # push the element at that integer to our output array and delete that
-        # element from our input array
-        randomized << input.delete_at(randomized_index)
-    end
+        until original_array.length == 0
+            # initialize a random integer within the array's # of elements
+            randomized_index = rand(original_array.length)
 
-    return randomized
+            # push the element at that integer to our output array and delete that
+            # element from our input array
+            randomized << original_array.delete_at(randomized_index)
+        end
+
+        return randomized
+    end
 end

chapter_13_creating_new_classes_changing_existing_ones/orange_tree.rb

@@ -0,0 +1,64 @@
+# =============================================================================
+# Orange Tree 
+# =============================================================================
+
+class OrangeTree
+    def initialize(name=nil)
+        @height = 0
+        @age = 0
+        @name = name
+        @oranges = 0
+    end
+
+    def height
+        one_year_passes
+        return @height
+    end
+
+    def name
+        one_year_passes
+        return @name
+    end
+
+    def count_the_oranges
+        one_year_passes
+        return @oranges
+    end
+
+    def pick_an_orange
+        if @oranges >= 1
+            puts "You have picked an orange."
+            @oranges -= 1
+            puts "The tree now has #{@oranges} fruit left."
+        else
+            puts "You don't have any oranges to pick."
+        end
+
+        one_year_passes
+    end
+
+    def continue
+        one_year_passes
+    end
+
+    private
+    def one_year_passes
+        @height += 1
+        @age += 1
+
+        if @age >= 13
+            puts "Your orange tree #{@name} has withered away and died."
+            exit
+        elsif @age >= 3
+            random = 0
+            loop do 
+                random = rand(@age)
+                break if random > 0
+            end
+
+            @oranges = random * 2
+        end
+
+        print "\nYour tree has grown. It is now #{@height} feet tall.\nIt is has #{@oranges} fruit.\n"
+    end
+end

chapter_13_creating_new_classes_changing_existing_ones/shuffle.rb

@@ -0,0 +1 @@
+../chapter_10_recursion/shuffle.rb