Code shared from the Rust Playground

playground.rs

// Cargo.toml dependencies:
// serde = { version = "1.0", features = ["derive"] }
// chrono = "0.4"
// rand_0_8_5 = { package = "rand", version = "0.8.5" }

use serde::Serialize;
use chrono::Utc;
use rand_0_8_5::{thread_rng as rng_legacy, Rng as RngLegacy};

/// Speed of light in vacuum (m/s)
const SPEED_OF_LIGHT: f64 = 299_792_458.0;

#[derive(Debug, Serialize)]
struct EmissionLine {
    element: String,
    wavelength_nm: f64,
    frequency_thz: f64,
}

impl EmissionLine {
    fn from_wavelength(element: &str, nm: f64) -> Self {
        // Frequency f = c / lambda
        // Convert nm to meters (1e-9) and result to THz (1e-12)
        let frequency_hz = SPEED_OF_LIGHT / (nm * 1e-9);
        Self {
            element: element.to_string(),
            wavelength_nm: nm,
            frequency_thz: frequency_hz / 1e12,
        }
    }
}

fn main() {
    let now = Utc::now();
    println!("--- Element Spectroscopy Report [{}] ---", now.format("%Y-%m-%d %H:%M:%S"));

    // Notable visible emission lines for Titanium (Ti I) in nanometers
    let ti_wavelengths = vec![
        365.35, 399.86, 430.59, 453.32, 498.17, 500.72, 517.37, 519.30, 625.81
    ];

    let mut spectrum: Vec<EmissionLine> = ti_wavelengths
        .into_iter()
        .map(|wl| EmissionLine::from_wavelength("Titanium", wl))
        .collect();

    // Demonstrate versioned RNG usage from your template
    let mut v8 = rng_legacy();
    let noise: f64 = v8.gen_range(-0.01..0.01);

    println!("{:<12} | {:<15} | {:<15}", "Element", "Wavelength (nm)", "Frequency (THz)");
    println!("{:-<48}", "");

    for line in &spectrum {
        println!(
            "{:<12} | {:<15.2} | {:<15.2}",
            line.element, 
            line.wavelength_nm + noise, // Applying slight legacy RNG jitter
            line.frequency_thz
        );
    }

    // Example of serializing the strongest line
    if let Ok(json) = serde_json::to_string(&spectrum[0]) {
        println!("\nMetadata for strongest line: {}", json);
    }
}