🕒 Time in Rust

✅ From the Standard Library (std::time)

use std::time::{SystemTime, UNIX_EPOCH, Duration};

---

⏰ Get current system time (as UNIX timestamp)

let now = SystemTime::now();
let since_epoch = now.duration_since(UNIX_EPOCH)?;
println!("Seconds since epoch: {}", since_epoch.as_secs());

---

🕑 Measure elapsed time

let start = std::time::Instant::now();

// some computation
std::thread::sleep(Duration::from_secs(2));

let duration = start.elapsed();
println!("Time elapsed: {:?}", duration);

---

🧭 Using chrono crate (Recommended for more flexibility)

Add to Cargo.toml:

chrono = "0.4"

use chrono::{Local, Utc, Datelike, Timelike};

---

📆 Get current date/time

let now = Local::now(); // or Utc::now()
println!("Local: {}", now);

🧩 Access parts

println!(
    "{}-{:02}-{:02} {}:{:02}:{:02}",
    now.year(),
    now.month(),
    now.day(),
    now.hour(),
    now.minute(),
    now.second(),
);

---

📅 Parse and format dates

use chrono::NaiveDateTime;

let dt = NaiveDateTime::parse_from_str("2025-06-01 14:30:00", "%Y-%m-%d %H:%M:%S")?;
println!("Parsed datetime: {}", dt);

let formatted = now.format("%Y-%m-%d %H:%M:%S").to_string();
println!("Formatted: {}", formatted);

---

✅ Summary Table

Task	std::time	chrono
Get current time	SystemTime::now()	Local::now() / Utc::now()
Time since epoch	duration_since(...)	timestamp()
Measure elapsed time	Instant::now().elapsed()	Utc::now() - other_time
Formatting / Parsing	❌ (Manual only)	✅ Built-in with format()
Date math (add/sub)	Manual with Duration	Easy with +/- and Duration