addlisting to code block

Author: habibasorour

source/ch4_conditionals.ptx

@@ -460,7 +460,8 @@ Java also provides the ternary operator <c>condition ? valueIfTrue : valueIfFals
 <p>
 Using this operator can make code shorter and more readable in cases where a simple conditional assignment is needed. See the following as an example where we see the same logic implemented in two different ways.
 </p>
-        <program xml:id="java-ternary" interactive="activecode" language ="java">
+        <listing xml:id="java-ternary">
+        <program interactive="activecode" language ="java">
             <code>
 public class Ternary {
     public static void main(String[] args) {
@@ -484,6 +485,7 @@ public class Ternary {
 }
             </code>
         </program>
+        </listing>
 
         <p>
             In this example we are using this ternary operator to assign a value to <c>a</c> based on whether <c>a</c> is even or odd. If <c>a</c> is even, it will be squared; if odd, it will be instead be calculated as <c>3 * x - 1</c>. This is a concise way to write conditional assignments in Java. However, you might want to use it sparingly, as it can make code less readable if overused or used with complex expressions.