find the standard deviation of all elements in an array in rust

To find the standard deviation of all elements in an array in Rust, we need to do the following steps:

1. Find the mean of the array elements
2. Calculate the variance of the array elements
3. Take the square root of the variance to obtain the standard deviation

Here is a Rust code snippet that demonstrates how to find the standard deviation of all elements in an array:

main.rs
use std::f64;

fn main() {
    let arr = [1.0, 2.0, 3.0, 4.0, 5.0];
    let mean = arr.iter().sum::<f64>() / arr.len() as f64;
    let variance = arr.iter().map(|x| (x - mean).powi(2)).sum::<f64>() / arr.len() as f64;
    let sd = f64::sqrt(variance);
    println!("Standard deviation is: {:.2}", sd);
}
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In this code, we use the built-in sum method to obtain the sum of all array elements. We also use len() to get the length of the array, and powi() to raise the result to a power. Finally, we use the square-root function from the f64 module to compute the standard deviation of the array elements.

Note that we have formatted the output to two decimal places using :.2.