Improved

Author: sajith

CMakeLists.txt

@@ -28,4 +28,5 @@ add_subdirectory(plant-care-better)
 #add_executable(isp_device_better ISP/isp_device_example_better.cpp)
 #add_executable(isp_multiple_inheritance ISP/isp_multiple_inheritance.cpp)
 #add_executable(dip_lamp DIP/dip_lamp_example.cpp)
-add_executable(dip_lamp_better DIP/dip_lamp_example_better.cpp)
+#add_executable(dip_lamp_better DIP/dip_lamp_example_better.cpp)
+add_executable(dip_lamp_better2 DIP/dip_lamp_example_better2.cpp)

DIP/dip_lamp_example_better2.cpp

@@ -0,0 +1,87 @@
+//
+// Created by sajith on 4/23/21.
+//
+
+#include <iostream>
+
+
+template<typename T> concept Switchable =
+requires(T t)
+{
+    t.switchOn();
+    t.switchOff();
+};
+
+// This is our explicit abstraction
+
+// Client module, policy, higher layer
+template<typename Switchable>
+class Button
+{
+    Switchable &switchable;
+    bool on = false;
+
+public:
+    Button(Switchable &switchable) : switchable{switchable} {}
+
+    void toggle()
+    {
+        if (on)
+        {
+            switchable.switchOff();
+        } else
+        {
+            switchable.switchOn();
+        }
+
+        on = !on;
+    }
+};
+
+
+// service module, implementation details, lower layer
+
+class Lamp1
+{
+public:
+    void switchOn()
+    {
+        std::cout << "Lamp1 is on\n";
+    }
+
+    void switchOff()
+    {
+        std::cout << "Lamp1 is off\n";
+    }
+};
+
+class Lamp2
+{
+public:
+    void switchOn()
+    {
+        std::cout << "Lamp2 is on\n";
+    }
+
+    void switchOff()
+    {
+        std::cout << "Lamp2 is off\n";
+    }
+};
+
+
+int main()
+{
+    Lamp1 lamp1;
+    Button<Lamp1> button1(lamp1);
+    button1.toggle();
+    button1.toggle();
+
+    Lamp2 lamp2;
+    Button<Lamp2> button2(lamp2);
+    button2.toggle();
+    button2.toggle();
+
+    return 0;
+}
+