Finish figures and listings

Listings/catsexample.xml

@@ -4,6 +4,7 @@
    author="Admin" inputFile="titlos.in" outputFile="titlos.out">
 
 <Keyword code="alg.geometry"/>
+
 <ProblemStatement>
   Problem statement and description.
 </ProblemStatement>
@@ -17,15 +18,15 @@
 </OutputFormat>
 
 <ProblemConstraints>
-$1 \le m \le 100$, $-100 \le x_i \le 100, 0 &lt; y_i \le 100$
+  $1 \le m \le 100$, $-100 \le x_i \le 100, 0 &lt; y_i \le 100$
 </ProblemConstraints>
 
 <Sample rank="1">
-  <SampleIn>
-3
-1 2 3
-4 5 6
-7 8 9
+<SampleIn>
+  3
+  1 2 3
+  4 5 6
+  7 8 9
 </SampleIn>
 <SampleOut>
   6
@@ -38,7 +39,10 @@ $1 \le m \le 100$, $-100 \le x_i \le 100, 0 &lt; y_i \le 100$
 <Import guid="std.testlib.1.1" type="checker" />
 <Checker name="ch" src="check.dpr" style="testlib"/>
 
-<TestRange from="1" to="42"><In src="tests/%0n"/><Out use="sol"/></TestRange>
+<TestRange from="1" to="42">
+  <In src="tests/%0n"/>
+  <Out use="sol"/>
+</TestRange>
 
 </Problem>
 </CATS>

Listings/pdoexamples.php

 <?php
+// Connecting to a MySQL database
 $user = "root";
 $pass = "root";
-$dsn = "mysql:host=localhost;dbname=test";
 $charset = "utf8";
+$dsn = "mysql:host=localhost;dbname=test;charset=$charset";
 
-$dbh = new PDO('mysql:host=localhost;dbname=test;charset=$charset', $user, $pass);
-?>
-
-<?php
+$db = new PDO($dsn, $user, $pass);
 
-$query = "SELECT * FROM foo WHERE bar = " . $db->quote($zip);
+// Executing a simple query
+$val = 42;
 
+$query = "SELECT * FROM foo WHERE bar = " . $db->quote($val);
 $result = $db->query($query);
 
 while($row = $result->fetch(PDO::FETCH_ASSOC)) {
     print_r($row);
 }
-?>
 
-<?php
-$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value) VALUES (:name, :value)");
+// Sequential executions of a prepared statement
+$query = "INSERT INTO REGISTRY (name, value)
+          VALUES (:name, :value)";
+$stmt = $db->prepare($query);
 $stmt->bindParam(':name', $name);
 $stmt->bindParam(':value', $value);
 
-// insert one row
+// First execution
 $name = 'one';
 $value = 1;
 $stmt->execute();
 
-// insert another row with different values
+// Second execution with different values
 $name = 'two';
 $value = 2;
 $stmt->execute();