The idea behind functions is very simple – split up a large program into smaller chunks that can be reasoned more easily and allow the reuse of the code to avoid repetition. This second point is known as the Don't Repeat Yourself (DRY) principle. The more times you write the same code, the higher the chances of a bug creeping in.
When this principle is taken to its logical conclusion, you will have created a program that consists of many small functions, each doing a single thing; this is similar to the Unix principle of using small programs, where each program does a single job.
The same principle applies to the code inside a function. Typically, in Java, for example, a large function or method might be broken down by calling several support functions declared in either the same class or a helper class that contains static methods.
Kotlin allows us...