Lecture 18

Abstraction

What is abstraction?:

hiding away the implementation details
read more at http://en.wikipedia.org/wiki/Abstraction_(computer_science) (only the first paragraph is enough)

Why is abstraction important?:

it gets programming out of the way so you can focus on the problem you want to solve
it makes code more maintainable and extensible (e.g. easier to read, update, and debug)
some reading the code later can focus on "what" the code is doing
when they've found the area of the code they want to focus on then they can dig deeper and focus "how" the code is working

How to abstract?:

there's no exact science
there are some guidelines
abstraction really is about writing high quality code, which is hard to measure, quantify, or deem to be right or wrong
sometimes it could be personal preference
it is possible to keep on abstracting and making code more readable indefinitely, but sometimes you just need to choose a point to stop
I just want to introduce you to the concept so you're aware of it

Let us refactor (e.g. update the code while preserving it's functionalities) refactored_net_balance.c to abstract away some implementation details:

Let's Compare:

Let's just compare what matters:

Things to Note:

easier to read and understand
shorter, cleaner, and less cluttered
difference might be small for this simple example, but as a program gets larger, difference will be much larger
more smaller files is usually better than one big file
removed nested if statment

a file named UHusername_18_1.c
a file named UHusername_18_1_macros.h
a file named UHusername_18_1_functions.c
a file named UHusername_18_1_functions.h
- zhaol_18_1.c
- zhaol_18_1_macros.h
- zhaol_18_1_functions.c
- zhaol_18_1_functions.h
refactor refactored_net_balance.c so the block of code to display the accounts summary information is performed using a function:

Note:
- be sure to update the include statements so they are using the new filenames
- be sure to define the new function (display_accounts_summary_information) in the helper_functions file (i.e. zhaol_18_1_functions.c)
- be sure to use this function prototype:
```
void display_accounts_summary_information(
  int total_number_of_accounts,
  float total_amount_in_accounts,
  float total_minimum_balance_fees,
  int total_accounts_with_minimum_balance_fees);
```