In the real world requirements are always changing, and it’s up to you to roll with these changes and keep your customer satisfied.
The one constant in software analysis and design is
Requirements always change. If you have got good use cases, though you can usually change your software quickly to adjust to those new requirements.
1- The Main Path should be what you want to have happen most of the time.
2- The Alternate Path is one or more steps that a use case has that are optional, or provide
alternate ways to work through the use case.
3- A complete path through a use case from the first step to the last, is called a scenario.
4- Any time you change your use case, you need to go back and check your requirements.
5- Duplicate code is a bad idea.
6- The last note is
Now we will add some new tools that we learn it in this chapter:-
And the OO Principles that we learn:-
Finally the source code for Modified Dog Door System that he talk about it in this chapter you can find it Here. I implement it in C#.