We have refreshed our experience in the C++ language by completing this chapter. Now we know that C++ is more modern, and it comes with numerous features that assist us in creating a better program. We can use the Standard Library to make our code efficient since we don't need to write too many redundant functions. We can use the Lambda expression to make our code tidy, easy to read, and easy to maintain. We can also use the smart pointer so we don't need to worry about memory management anymore. Moreover, as we are concerned about immutability in functional programming, we will discuss that deeper in the next chapter; the use of tuples can help us ensure that no global state is involved in our code.
In the next chapter, we will discuss First-Class and Pure Function, which is used to purify our class and ensure that no outside state is involved in the current function. As a result, it will avoid side effects in our functional code.