Code maintenance??

Question

How do I know if my code is easier to maintain or not?
Also how to write codes which can be easily maintained.

Answer 1

you know it's easy to maintain when you want to add a feature or remove one, without having a headache or rewriting from scratch, when it's well commented.
to make it maintainable :
+ make it modular, divide it into modules and make them independent as much as you can.
+ design your application before you start making it.
+ comment your code.
+ make it simple, don't complicate things when you don't have to.
+ use a software versioning control system to track the changes you make to your code (gitlab, github, svn....)

Answer 2

I want to add:

Concentrate on writing readable code.

Especially, find good, fitting, self-explanatory names for all your variables, functions, classes etc.