How to write an adjustable ABAP program?

I have experienced in developing programs in ABAP and through it would like to know how can I code keeping future changes in mind.

For example recently I developed a program for a customized process on client side and initially requirements were simple and program was done.

But few weeks later came changes that were critical and although I accommodated them it came at expense of code readability and performance.

Few more months later came few more changes, and at this moment I was thoroughly confused as to what I had done in there making myself confused by my own programming.

So I would really like to know as to what methodology you gurus adopt for these kind of scenarios assuming changes to be inevitable .

regards,

Umar Abdullah

There will always be change. The techniques of Agile Software Development enable you to build changeability into your design and keep your code maintainable throughout its lifecycle.

Some key ideas at a glance:

• Write automatic unit tests to be able to refactor your code without breaking existing functionality. Keywords: Unit Testing, Test Pyramid.
• Split big changes into many small steps that you integrate and test in a continuous manner. Keywords: Continuous Integration.
• Write clean code to structure your code into reusable, pluggable components. Keywords: Clean Code, Clean Architecture. Clean ABAP may help.