Welcome, wise explorer! We are embarking on a journey through the world of Rust. Our focus for today is Rust functions. A function in Rust behaves like a recipe: it takes in certain ingredients, or "arguments", processes them according to a set of instructions, and then produces an output, or a "return value".

For instance, consider a function in a weather forecasting app. This function takes the current temperature and humidity as input, computes the likelihood of precipitation, and then displays the expected weather outcome.

Are you ready for an adventure into the world of Rust functions? Let's begin!

Creating a function in Rust involves the use of the keyword fn, the name of the function, parentheses (), and curly braces {}. Here is an example:

In this function, hello_world is the name of the function. The body of the function, which is encapsulated within the curly braces, performs the operation of printing out the phrase "Hello, World!". Now that we've created our first function, let's understand how to use it.

In Rust, like many other languages, functions can be called within other functions, including within the main function itself. This is crucial in structuring our program: we can break down complex tasks into digestible sub-tasks. Each sub-task can be defined as a function and then executed in a particular order within the function or even other functions.