[MUSIC] Hello again. Formal methods are not used much and
when they are, they provide a high level of assurance
that a program will work is expected. These methods are complex and
require specialized skills and tools, but we can draw lessons from
the techniques used and they will improve the security and
robustness of the code we developed. This module picks up where
the last one left off. Instead of examining problem code, we will look at informal, formal and
ad hoc programming methodologies. Will consider how each is used
to construct, evaluate and troubleshoot your programs. We will then look at two critical types of
programs which must be secure logins and authenticating users. At the end of this lesson, you'll be able
to describe how to use techniques that mimic formal methods to improve
the robustness and security of programs. You'll also be able to compare and
contrast formal, informal and ad hoc programming methodologies. Let's get started.