One of the most important things a programmer has to know and learn is proper code design, structuring of the code, etc. This may not be imperative for you if you’re just starting out, but sooner or later you’ll be able to spot the patterns and realize that your current way of doing things is not optimal but rather cumbersome. This is when you start to separate things into modules and you begin to design your code with more meaning and purpose.

By breaking your code into modules or “classes” you can have a finer granularity of the code itself, you can encapsulate the base code and work on top of it, you can also reuse the code in other projects if you have a good design. An example would be a log library (for logging useful debugging information onto text files) with proper design and care you’ll be able to use the same library in almost all of your projects with little to no modification at all.
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