In this section, we will cover the core concepts behind functional programming and give you the necessary knowledge to understand and write simple functional programs.
By the end of this section, you should have a good understanding of the core concepts behind functional programming, such as:
Writing and using pure functions
Using immutable classes instead of mutable classes
Writing and using higher-order functions
At the very core of functional programming is the concept of a
pure function. A function is pure if it doesn't have any side effects, that is, the function simply computes a result based on the arguments to the function and does nothing else.
Examples of side effects are modifying variables, setting fields on objects, performing input/output operations such as reading or writing a file, printing values to the console, and many more.
Let's look at some examples of both
pure and
impure functions to better understand...