Using ConcurrentStack

In this section, we are going to experiment with BlockingCollection<T> and ConcurrentStack<T>. In the first example in this chapter, we used BlockingCollection<T> to read the words that started with a specific letter from the book Ulysses. We are going to make a copy of that project and change the code that reads the lines of text to use ConcurrentStack<T> inside BlockingCollection<T>. This will make the lines output in reverse order because a stack uses last in, first out (LIFO) logic. Let’s get started!

1. Make a copy of the ParallelExtras.BlockingCollection project from this chapter or modify the existing project if you prefer.
2. Open MainWindow.xaml.cs and modify the LoadBookLinesFromFile method to pass a new ConcurrentStack<string> to the constructor of BlockingCollection<string>:

   private async Task<BlockingCollection<string>> 
       LoadBookLinesFromFile()
   {
     ...