From 2d60f640eb526ba94ecf0355709e1655beb77ab7 Mon Sep 17 00:00:00 2001
From: Ian Dinwoodie <dinwoodieian@gmail.com>
Date: Mon, 29 Apr 2019 20:26:55 -0400
Subject: [PATCH] Added flyweight example.

---
 README.md | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 96 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index af2749d..87adca1 100644
--- a/README.md
+++ b/README.md
@@ -1489,7 +1489,102 @@ repeated representation would use an unacceptable amount of memory.
 
 #### Programmatic Example
 
-TODO
+Translating our tea example from above. First of all we have tea types and tea
+maker
+
+```cpp
+class Tea
+{
+  public:
+    typedef std::shared_ptr<Tea> ptr_t;
+};
+
+class TeaMaker
+{
+  public:
+    typedef std::shared_ptr<TeaMaker> ptr_t;
+
+    Tea::ptr_t make(const std::string& preference)
+    {
+      auto match = availableTea_.find(preference);
+      if (match == availableTea_.end()) {
+        availableTea_[preference] = std::make_shared<Tea>();
+      }
+
+      return availableTea_[preference];
+    }
+
+    int getPreferenceCount(void)
+    {
+      return availableTea_.size();
+    }
+
+  private:
+    std::unordered_map<std::string, Tea::ptr_t> availableTea_;
+};
+```
+
+Then we have the tea shop which takes orders and serves them
+
+```cpp
+class TeaShop
+{
+  public:
+    TeaShop(TeaMaker::ptr_t maker)
+        : maker_(maker)
+    {
+    }
+
+    void takeOrder(const std::string& preference, int table)
+    {
+      orders_[table] = maker_->make(preference);
+    }
+
+    void serve(void)
+    {
+      for (auto order : orders_) {
+        std::cout << "Serving tea to table " << order.first << std::endl;
+      }
+    }
+
+    int getPreferenceCount(void)
+    {
+      return maker_->getPreferenceCount();
+    }
+
+  private:
+    TeaMaker::ptr_t maker_;
+    std::unordered_map<int, Tea::ptr_t> orders_;
+};
+```
+
+Here is how this can be used:
+
+```cpp
+TeaMaker::ptr_t maker = std::make_shared<TeaMaker>();
+TeaShop shop(maker);
+
+// No orders have been taken, so there are no available teas.
+std::cout << shop.getPreferenceCount() << std::endl; // Output: 0
+
+// Take some orders.
+shop.takeOrder("half sugar", 1);
+shop.takeOrder("with milk", 2);
+shop.takeOrder("with boba", 5);
+
+// We create a new batch of tea for each preference.
+std::cout << shop.getPreferenceCount() << std::endl; // Output: 3
+
+// Take an order with a previously requested preference.
+shop.takeOrder("half sugar", 4);
+
+// Since we have some tea from the last time this request was made, no new
+// batch was created.
+std::cout << shop.getPreferenceCount() << std::endl; // Output: 3
+
+// Serve the customers.
+shop.serve(); 
+```
 
 #### When To Use