Added adapter example source code.

examples/structural/adapter.cpp

@@ -0,0 +1,73 @@
+#include <iostream>
+#include <memory>
+
+class Lion
+{
+  public:
+    virtual void roar(void) = 0;
+};
+
+class AfricanLion : public Lion
+{
+  public:
+    void roar(void)
+    {
+      std::cout << "*African lion roar*" << std::endl;
+    }
+};
+
+class AsianLion : public Lion
+{
+  public:
+    void roar(void)
+    {
+      std::cout << "*Asian lion roar*" << std::endl;
+    }
+};
+
+class Hunter
+{
+  public:
+    void hunt(Lion& lion)
+    {
+      lion.roar();
+    }
+};
+
+class WildDog
+{
+  public:
+    typedef std::shared_ptr<WildDog> ptr_t;
+    void bark(void)
+    {
+      std::cout << "*wild dog bark*" << std::endl;
+    }
+};
+
+class WildDogAdapter : public Lion
+{
+  public:
+    WildDogAdapter(WildDog::ptr_t dog)
+        : dog_(dog)
+    {
+    }
+
+    void roar(void)
+    {
+      dog_->bark();
+    }
+
+  private:
+    WildDog::ptr_t dog_;
+};
+
+int main()
+{
+  WildDog::ptr_t wildDog = std::make_shared<WildDog>();
+  WildDogAdapter wildDogAdapter(wildDog);
+
+  Hunter hunter;
+  hunter.hunt(wildDogAdapter); // Output: *wild dog bark*
+
+  return 0;
+}