code refactoring: fix memory leaks, code style, etc.

visitor/Visitor.cpp

@@ -19,10 +19,13 @@ class ConcreteElementB;
  * declares a Visit operation for each class of ConcreteElement
  * in the object structure
  */
-class Visitor {
+class Visitor
+{
 public:
-  virtual void visitElementA(ConcreteElementA *element) = 0;
-  virtual void visitElementB(ConcreteElementB *element) = 0;
+  virtual ~Visitor() {}
+  
+  virtual void visitElementA( ConcreteElementA* const element ) = 0;
+  virtual void visitElementB( ConcreteElementB* const element ) = 0;
   // ...
 };
 
@@ -32,25 +35,35 @@ public:
  * a fragment of the algorithm defined for the corresponding class
  * of object in the structure
  */
-class ConcreteVisitor1 : public Visitor {
+class ConcreteVisitor1 : public Visitor
+{
 public:
-  void visitElementA(ConcreteElementA *) {
+  ~ConcreteVisitor1() {}
+  
+  void visitElementA( ConcreteElementA* const )
+  {
     std::cout << "Concrete Visitor 1: Element A visited." << std::endl;
   }
-
-  void visitElementB(ConcreteElementB *) {
+  
+  void visitElementB( ConcreteElementB* const )
+  {
     std::cout << "Concrete Visitor 1: Element B visited." << std::endl;
   }
   // ...
 };
 
-class ConcreteVisitor2 : public Visitor {
+class ConcreteVisitor2 : public Visitor
+{
 public:
-  void visitElementA(ConcreteElementA *) {
+  ~ConcreteVisitor2() {}
+  
+  void visitElementA( ConcreteElementA* const )
+  {
     std::cout << "Concrete Visitor 2: Element A visited." << std::endl;
   }
-
-  void visitElementB(ConcreteElementB *) {
+  
+  void visitElementB( ConcreteElementB* const )
+  {
     std::cout << "Concrete Visitor 2: Element B visited." << std::endl;
   }
   // ...
@@ -60,9 +73,12 @@ public:
  * Element
  * defines an accept operation that takes a visitor as an argument
  */
-class Element {
+class Element
+{
 public:
-  virtual void accept(Visitor &visitor) = 0;
+  virtual ~Element() {}
+  
+  virtual void accept( Visitor &visitor ) = 0;
   // ...
 };
 
@@ -70,18 +86,26 @@ public:
  * Concrete Elements
  * implement an accept operation that takes a visitor as an argument
  */
-class ConcreteElementA : public Element {
+class ConcreteElementA : public Element
+{
 public:
-  void accept(Visitor &visitor) {
-    visitor.visitElementA(this);
+  ~ConcreteElementA() {}
+  
+  void accept( Visitor &visitor )
+  {
+    visitor.visitElementA( this );
   }
   // ...
 };
 
-class ConcreteElementB : public Element {
+class ConcreteElementB : public Element
+{
 public:
-  void accept(Visitor &visitor) {
-    visitor.visitElementB(this);
+  ~ConcreteElementB() {}
+  
+  void accept( Visitor &visitor )
+  {
+    visitor.visitElementB( this );
   }
   // ...
 };
@@ -91,15 +115,15 @@ int main()
 {
   ConcreteElementA elementA;
   ConcreteElementB elementB;
-
+  
   ConcreteVisitor1 visitor1;
   ConcreteVisitor2 visitor2;
-
+  
   elementA.accept(visitor1);
   elementA.accept(visitor2);
-
+  
   elementB.accept(visitor1);
   elementB.accept(visitor2);
-
+  
   return 0;
 }