Added prototype example source code.

examples/creational/prototype.cpp

@@ -0,0 +1,49 @@
+#include <iostream>
+#include <string>
+
+class Sheep
+{
+  public:
+    Sheep(const std::string& name, const std::string& category)
+        : name_(name), category_(category)
+    {
+    }
+
+    void setName(const std::string name)
+    {
+      name_ = name;
+    }
+
+    std::string getName(void)
+    {
+      return name_;
+    }
+
+    void setCategory(const std::string category)
+    {
+      category_ = category;
+    }
+
+    std::string getCategory(void)
+    {
+      return category_;
+    }
+
+  private:
+    std::string name_;
+    std::string category_;
+};
+
+int main()
+{
+  Sheep original = Sheep("Molly", "Mountain Sheep");
+  std::cout << original.getName() << std::endl; // Output: Molly
+  std::cout << original.getCategory() << std::endl; // Output: Mountain Sheep
+
+  Sheep clone = original;
+  clone.setName("Dolly");
+  std::cout << clone.getName() << std::endl; // Output: Dolly
+  std::cout << clone.getCategory() << std::endl; // Output: Mountain Sheep
+
+  return 0;
+}