Rust Programming Cookbook

How to do it...

Lifetimes can be explored in a few steps:

1. Create a new project using cargo new lifetimes --lib and open it in your favorite editor.
2. Let's start with a simple function that takes in a reference that might not outlive the function! Let's make sure that the function and the input parameter are on the same lifetime:

// declaring a lifetime is optional here, since the compiler automates this////// Compute the arithmetic mean/// pub fn mean<'a>(numbers: &'a [f32]) -> Option<f32> {    if numbers.len() > 0 {        let sum: f32 = numbers.iter().sum();        Some(sum / numbers.len() as f32)    } else {        None    }} 

3. Where the lifetime declaration is required is in structs. Therefore, we define the base struct first. It comes with a lifetime annotation ...