From d7a25a0efc8638b078bef5fa529a3c790257168d Mon Sep 17 00:00:00 2001
From: Shaun Reed <shaunrd0@gmail.com>
Date: Tue, 11 May 2021 17:39:36 -0400
Subject: [PATCH] Add example of prototype pattern in C++

---
 cpp/patterns/CMakeLists.txt           |  1 +
 cpp/patterns/prototype/CMakeLists.txt | 20 +++++++++
 cpp/patterns/prototype/main.cpp       | 21 ++++++++++
 cpp/patterns/prototype/prototype.cpp  |  8 ++++
 cpp/patterns/prototype/prototype.hpp  | 58 +++++++++++++++++++++++++++
 5 files changed, 108 insertions(+)
 create mode 100644 cpp/patterns/prototype/CMakeLists.txt
 create mode 100644 cpp/patterns/prototype/main.cpp
 create mode 100644 cpp/patterns/prototype/prototype.cpp
 create mode 100644 cpp/patterns/prototype/prototype.hpp

diff --git a/cpp/patterns/CMakeLists.txt b/cpp/patterns/CMakeLists.txt
index d2f4bde..7f365d2 100644
--- a/cpp/patterns/CMakeLists.txt
+++ b/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)
diff --git a/cpp/patterns/prototype/CMakeLists.txt b/cpp/patterns/prototype/CMakeLists.txt
new file mode 100644
index 0000000..d779585
--- /dev/null
+++ b/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)
diff --git a/cpp/patterns/prototype/main.cpp b/cpp/patterns/prototype/main.cpp
new file mode 100644
index 0000000..57439b9
--- /dev/null
+++ b/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();
+}
diff --git a/cpp/patterns/prototype/prototype.cpp b/cpp/patterns/prototype/prototype.cpp
new file mode 100644
index 0000000..f37fe0c
--- /dev/null
+++ b/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);
+}
diff --git a/cpp/patterns/prototype/prototype.hpp b/cpp/patterns/prototype/prototype.hpp
new file mode 100644
index 0000000..140bbdc
--- /dev/null
+++ b/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