Added Bubble Sort in Crystal (#319)

* Added Bubble Sort in Crystal
* added crystal-lang in book.json

Author: NIFR91

CONTRIBUTORS.md

@@ -49,3 +49,5 @@ Max Weinstein
 Gibus Wearing Brony
 <br>
 Arun Sahadeo
+<br>
+NIFR91

book.json

@@ -116,7 +116,12 @@
         {
           "lang": "lua",
           "name": "Lua"
+        },
+        {
+          "lang": "crystal",
+          "name": "Crystal"
         }
+
       ]
     }
   }

contents/bubble_sort/bubble_sort.md

@@ -40,6 +40,8 @@ This means that we need to go through the vector $$\mathcal{O}(n^2)$$ times with
 [import:2-13, lang:"ti-83_basic"](code/ti83basic/BUBLSORT.txt)
 {% sample lang="ruby" %}
 [import:3-13, lang:"ruby"](code/ruby/bubble.rb)
+{% sample lang="crystal" %}
+[import:1-11, lang:"crystal"](code/crystal/bubble.cr)
 {% endmethod %}
 
 ... And that's it for the simplest bubble sort method.
@@ -85,6 +87,8 @@ Program.cs
 [import, lang:"ti-83_basic"](code/ti83basic/BUBLSORT.txt)
 {% sample lang="ruby" %}
 [import, lang:ruby"](code/ruby/bubble.rb)
+{% sample lang="crystal" %}
+[import, lang:"crystal"](code/crystal/bubble.cr)
 {% endmethod %}
 
 <script>

contents/bubble_sort/code/crystal/bubble.cr

@@ -0,0 +1,20 @@
+def bubble_sort(arr)
+  arr = arr.dup 
+  (0 ... arr.size).each do 
+    (0 ... arr.size-1).each do |k| 
+      if arr[k] > arr[k+1]
+        arr[k+1],arr[k] = arr[k],arr[k+1]
+      end
+    end
+  end 
+  arr
+end
+
+def main 
+  number = 10.times.map{rand(0..1_000)}.to_a 
+  pp "The array before sorting is #{number}"
+  number = bubble_sort number 
+  pp "The array after  sorting is #{number}"
+end 
+
+main