It is common to have multiple implementations to a given problem. In STL, for example, you can build a queue from a vector or a list, i.e,
std::queue<int, std::vector<int>> queue_using_vector;
std::queue<int, std::list<int>> queue_using_list;
Here, the container is provided as a template and therefore must be declared during compilation time. What if, here comes the question, I want to be able to choose its implementation during runtime and not compilation time?
In this post, I want to show the closest solution to the problem above. Consider the following scenario. I want to build a queue that uses some container APIs. The container can be either implemented through an array or through a list. I want to be able to decide this during runtime.
The code below shows a sketch of this design pattern. First, you must create its container APIs through a purely abstract class, i.e., define container interface. Then, you implement the APIs using two implementations: using an array and using a list. Next, you define a concrete container class which takes in either one of the implementation pointer. Finally, you can now use this concrete container class to implement a queue.
Cool, right? Happy hacking!
