added listing to text

Author: habibasorour

source/ch3_javadatatypes.ptx

@@ -826,7 +826,7 @@ public class HistoArray {
         </p>
 
         <p>
- Lets stay with a simple frequency counting example, only this time we will count the frequency of words in a document. A simple Python program for this job could look like this: 
+ Lets stay with a simple frequency counting example, only this time we will count the frequency of words in a document. <xref ref="python-word-count" text="type-global"/> shows a simple Python program for what this could look. 
         </p>
 
         <listing xml:id="python-word-count">
@@ -848,7 +848,7 @@ main()
         </listing>
 
         <p>
-    This program reads the file <c>alice30.txt</c> (which follows), and it then splits it into a list of words. Next it creates a dictionary called <c>count</c> which maps each word to the number of times that word occurs in the text. Finally, it prints out the words in alphabetical order along with their frequency.
+    This program reads the file <c>alice30.txt</c> in <xref ref="datafile-alice1" text="type-global"/>, and it then splits it into a list of words. Next it creates a dictionary called <c>count</c> which maps each word to the number of times that word occurs in the text. Finally, it prints out the words in alphabetical order along with their frequency.
         </p>
 
         <data xml:id="datafile-alice1">
@@ -877,7 +877,7 @@ main()
         </datafile>
         </data>
         <p>
- Notice that the structure of the program is very similar to the numeric histogram program. 
+ Notice that the structure of <xref ref="java-word-count" text="type-global"/> is very similar to the numeric histogram program. 
         </p>
 
         <listing xml:id="java-word-count">
@@ -922,7 +922,7 @@ public class HistoMap {
         </listing>
 
         <p>
- Improve the program above to remove the punctuation. 
+ Improve <xref ref="java-word-count" text="type-global"/> to remove the punctuation. 
         </p>
     </section>