Add example of prototype pattern in C++

cpp/patterns/CMakeLists.txt

@@ -19,4 +19,5 @@ add_subdirectory(singleton)
 add_subdirectory(adapter)
 add_subdirectory(bridge)
 add_subdirectory(factory)
+add_subdirectory(prototype)
 add_subdirectory(abstract-factory)

cpp/patterns/prototype/CMakeLists.txt

@@ -0,0 +1,20 @@
+###############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: A project for practicing the prototype C++ design pattern          ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+##############################################################################
+#
+cmake_minimum_required(VERSION 3.15)
+project(
+    #[[NAME]]   Prototype
+    VERSION     1.0
+    DESCRIPTION "An example of the prototype design pattern in C++"
+    LANGUAGES   CXX
+)
+add_compile_options("-Wall")
+
+add_library(prototype "prototype.cpp")
+add_executable(prototype-test "main.cpp")
+target_link_libraries(prototype-test prototype)

cpp/patterns/prototype/main.cpp

@@ -0,0 +1,21 @@
+
+#include <iostream>
+
+#include "prototype.hpp"
+
+int main(const int argc, const char * argv[]) {
+  // Create a new prototype factory
+  auto *factory = new PrototypeFactory;
+
+  // Create a gear by cloning from factory prototypes
+  auto *gear = factory->createPrototype(Types::GEAR);
+  gear->show();
+
+  // Create a spring by cloning from factory prototypes
+  auto *spring = factory->createPrototype(Types::SPRING);
+  spring->show();
+
+  // Create a spring by cloning from an existing spring
+  auto *otherSpring = spring->clone();
+  otherSpring->show();
+}

cpp/patterns/prototype/prototype.cpp

@@ -0,0 +1,8 @@
+
+#include "prototype.hpp"
+
+PrototypeFactory::PrototypeFactory()
+{
+  prototypes[Types::GEAR] = new Gear(1.5f);
+  prototypes[Types::SPRING] = new Spring(2.25f);
+}

cpp/patterns/prototype/prototype.hpp

@@ -0,0 +1,58 @@
+
+#ifndef PROTOTYPE_HPP
+#define PROTOTYPE_HPP
+
+#include <string>
+#include <utility>
+#include <unordered_map>
+#include <iostream>
+
+#include "prototype.hpp"
+
+enum Types {
+  GEAR = 0,
+  SPRING,
+};
+
+class Prototype {
+public:
+  Prototype(std::string name_, float price_) :
+      name(std::move(name_)), price(price_) {}
+  virtual ~Prototype() = default;
+
+  virtual Prototype *clone() const = 0;
+  virtual void setField(std::string field_) { field = std::move(field_);}
+
+  void show() const { std::cout << name << " with price: " << price << std::endl;}
+
+protected:
+  std::string name;
+  float price;
+  std::string field;
+};
+
+class Gear : public Prototype {
+public:
+  explicit Gear(const float &price_) : Prototype("Gear", price_) {}
+
+  Prototype *clone() const override { return new Gear(*this);}
+};
+
+class Spring : public Prototype {
+public:
+  explicit Spring(const float &price_) : Prototype("Spring", price_) {}
+
+  Prototype *clone() const override { return new Spring(*this);}
+};
+
+class PrototypeFactory {
+public:
+  PrototypeFactory();
+
+  Prototype *createPrototype(Types type) { return prototypes[type]->clone();}
+
+private:
+  std::unordered_map<Types, Prototype *> prototypes;
+};
+
+#endif // PROTOTYPE_HPP