Dependencies

A dependency refers to a specific software component or library that a project relies on to function properly.

For example, the hello-world program below uses the time library as a dependency:

use time; 

fn main(){
    println!("Hello world!!!");
    let wait_time : Duration = time::Duration::from_seconds(5);

    thread::sleep(wait_time);
}

Default dependencies

By default, all rust programs use the std library as a dependency. Even if you write a simple hello-world or an add-library, the contents of the std::prelude library get included as part of your code as if you had written it as follows...

use std::{self, prelude::*}; // this line is usually not there... but theoretically, 
                    // your compiler treats your code as if this line was explicitly declared here

fn main(){
    println!("Hello world!!!");
}

So ... what is the standard library? What is a prelude?