4. (Code Rewrite as a Useful Exercise in Code Versioning)

Consider the code in Section 11.4 to price an American down-and-out call option.

The objective of the current exercise is to manually re-engineer that code in a series of prototypes by using the lattice ADTS and Layer 2 algorithms. Test each prototype to make sure that it produces the same results as its predecessors.

What are the main advantages of the new code when compared with the original code?

This exercise can be seen as a follow-on from Exercise 1.