Rust program to demonstrate the num_days_from_ce() function

Rust | Date & Time Example: Write a program to demonstrate the num_days_from_ce() function.
Submitted by Nidhi, on November 09, 2021

Problem Solution:

In this program, we will get the current UTC date-time using Utc::now() function and get the days from Common Era began using num_days_from_ce() function.

Add Chrono date-time external library to your project

Create your project using the below command.
```
$cargo new datetime -bin
```
Goto the project folder cd datetime and edit Cargo.toml file.
```
$datetime>nano Cargo.toml
```
Then add dependency in Cargo.toml file
```
[dependencies]
chrono = "0.4"
```
After that, build your project using the below command
```
$datetime>cargo build
```
Then execute your project after modification in src/main.rs source file.
```
$datetime>cargo run
```

Program/Source Code:

The source code to demonstrate the num_days_from_ce() function is given below. The given program is compiled and executed on UBUNTU 18.04 successfully.

// Rust program to demonstrate the 
// num_days_from_ce() function

use chrono::{Datelike,Utc};

fn main() {
    let current = Utc::now();
    println!("The Common Era began {} days ago",current.num_days_from_ce());
}

Output:

$datetime> cargo run
   Compiling datetime v0.1.0 (/home/arvind/Desktop/rust/datetime)
    Finished dev [unoptimized + debuginfo] target(s) in 0.29s
     Running `target/debug/datetime`

The Common Era began 738093 days ago

Explanation:

In the above program, we imported the "Chrono" library to our project for performing date and time operations. We imported the Chrono library using the below line:

use chrono::Utc;

In the main() function, we got the current UTC date-time using the Utc::now() method and got the days from Common Era began using the num_days_from_ce() function and printed the result.