Add example of adapter pattern in C++

cpp/patterns/CMakeLists.txt

@@ -16,3 +16,7 @@ project(
 )
 
 add_subdirectory(singleton)
+add_subdirectory(adapter)
+add_subdirectory(bridge)
+add_subdirectory(factory)
+add_subdirectory(abstract-factory)

cpp/patterns/adapter/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 adapter C++ design pattern            ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+##############################################################################
+#
+cmake_minimum_required(VERSION 3.15)
+project(
+    #[[NAME]]   Adapter
+    VERSION     1.0
+    DESCRIPTION "An example of the adapter design pattern in C++"
+    LANGUAGES   CXX
+)
+add_compile_options("-Wall")
+
+add_library(adapter "adapter.cpp")
+add_executable(adapter-test "main.cpp")
+target_link_libraries(adapter-test adapter)

cpp/patterns/adapter/adapter.cpp

@@ -0,0 +1,2 @@
+
+#include "adapter.hpp"

cpp/patterns/adapter/adapter.hpp

@@ -0,0 +1,37 @@
+
+#ifndef ADAPTER_HPP
+#define ADAPTER_HPP
+
+#include <random>
+
+// Target implementation to adapt to a new interface
+class Add {
+public:
+  virtual ~Add() = default;
+
+  virtual int doMath(const int &a, const int &b) const { return a + b;}
+};
+
+// An adaptee with some useful behavior to adapt to our Add target
+class RandomNumber {
+public:
+  explicit RandomNumber(const int &max) : maxNum(max) { srand(time(nullptr));}
+
+  int getRandom() const { return rand() % maxNum;}
+
+private:
+  int maxNum;
+};
+
+// An adapter that combines behaviors of Add and RandomNumber
+class RandomAddAdapter : public Add {
+public:
+  explicit RandomAddAdapter(RandomNumber *random_) : random(random_) {}
+
+  int doMath(const int &a, const int &b) const override { return a + b + random->getRandom();}
+
+private:
+  RandomNumber *random;
+};
+
+#endif // ADAPTER_HPP

cpp/patterns/adapter/main.cpp

@@ -0,0 +1,20 @@
+
+#include <iostream>
+
+#include "adapter.hpp"
+
+int main(const int argc, const char * argv[]) {
+  const int a = 5;
+  const int b = 10;
+  std::cout << "A = " << a << "\nB = " << b << std::endl;
+
+  // Testing target implementation
+  Add adder;
+  std::cout << "Adding a + b: " << adder.doMath(a, b) << std::endl;
+
+  // Testing RandomAddAdapter using RandomNumber as the adaptee
+  RandomNumber *adaptee = new RandomNumber(100);
+  RandomAddAdapter *adapter = new RandomAddAdapter(adaptee);
+  std::cout << "\nAdding a + b + RandomNumber: " << adapter->doMath(a, b)
+            << std::endl;
+}