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

prototype/Prototype.cpp

@@ -14,9 +14,12 @@
  * Prototype
  * declares an interface for cloning itself
  */
-class Prototype {
+class Prototype
+{
 public:
-  virtual Prototype *clone() = 0;
+  virtual ~Prototype() {}
+  
+  virtual Prototype* clone() = 0;
   virtual std::string type() = 0;
   // ...
 };
@@ -25,23 +28,33 @@ public:
  * Concrete Prototype A and B
  * implement an operation for cloning itself
  */
-class ConcretePrototypeA : public Prototype {
+class ConcretePrototypeA : public Prototype
+{
 public:
-  Prototype *clone() {
-    return new ConcretePrototypeA;
+  ~ConcretePrototypeA() {}
+  
+  Prototype* clone()
+  {
+    return new ConcretePrototypeA();
   }
-  std::string type() {
+  std::string type()
+  {
     return "type A";
   }
   // ...
 };
 
-class ConcretePrototypeB : public Prototype {
+class ConcretePrototypeB : public Prototype
+{
 public:
-  Prototype *clone() {
-    return new ConcretePrototypeB;
+  ~ConcretePrototypeB() {}
+  
+  Prototype* clone()
+  {
+    return new ConcretePrototypeB();
   }
-  std::string type() {
+  std::string type()
+  {
     return "type B";
   }
   // ...
@@ -51,34 +64,52 @@ public:
  * Client
  * creates a new object by asking a prototype to clone itself
  */
-class Client {
+class Client
+{
 public:
-  static Prototype* make(int index) {
-    return types[index]->clone();
+  static void init()
+  {
+    types[ 0 ] = new ConcretePrototypeA();
+    types[ 1 ] = new ConcretePrototypeB();
+  }
+  
+  static void remove()
+  {
+    delete types[ 0 ];
+    delete types[ 1 ];
+  }
+  
+  static Prototype* make( const int index )
+  {
+    if ( index >= n_types )
+    {
+      return nullptr;
+    }    
+    return types[ index ]->clone();
   }
   // ...
 
 private:
-  static Prototype* types[2];
-};
-
-Prototype* Client::types[] =
-{
-  new ConcretePrototypeA,
-  new ConcretePrototypeB
-  // ...
+  static Prototype* types[ 2 ];
+  static int n_types;
 };
 
+Prototype* Client::types[ 2 ];
+int Client::n_types = 2;
 
 int main()
 {
-  Prototype* prototype;
-
-  prototype = Client::make(0);
-  std::cout << "Prototype: " << prototype->type() << std::endl;
-
-  prototype = Client::make(1);
-  std::cout << "Prototype: " << prototype->type() << std::endl;
-
+  Client::init();
+  
+  Prototype *prototype1 = Client::make( 0 );
+  std::cout << "Prototype: " << prototype1->type() << std::endl;
+  delete prototype1;
+  
+  Prototype *prototype2 = Client::make( 1 );
+  std::cout << "Prototype: " << prototype2->type() << std::endl;
+  delete prototype2;
+  
+  Client::remove();
+  
   return 0;
 }