"Unable to update registry: The server name or address could not be resolved" for a dependency - rust

Question

I am using Windows and facing below error. Not sure why it's not working.
C:\RUST\guess_game>cargo build
Updating registry `https://github.com/rust-lang/crates.io-index`
warning: spurious network error (2 tries remaining): [2/-1] failed to send request: The server name or address could not be resolved
warning: spurious network error (1 tries remaining): [2/-1] failed to send request: The server name or address could not be resolved
error: failed to load source for a dependency on `rand`
Caused by:
Unable to update registry https://github.com/rust-lang/crates.io-index
Caused by:
failed to fetch `https://github.com/rust-lang/crates.io-index`
Caused by:
[2/-1] failed to send request: The server name or address could not be resolved

Answer 1

You need internet access to download dependencies like rand:
Try these steps:
cargo new guessing_game --bin
cd guessing_game
cargo build
cargo run
Output:
C:\rust>cargo new guessing_game --bin
Created binary (application) `guessing_game` project
C:\rust>cd guessing_game
C:\rust\guessing_game>cargo build
Compiling guessing_game v0.1.0 (file:///C:/rust/guessing_game)
Finished dev [unoptimized + debuginfo] target(s) in 0.34 secs
C:\rust\guessing_game>cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
Running `target\debug\guessing_game.exe`
Hello, world!
Edit the Cargo.toml file:
[package]
name = "guessing_game"
version = "0.1.0"
authors = ["Your Name <you#example.com>"]
[dependencies]
rand = "0.3.14"
Output when there is no internet access:
C:\rust\guessing_game>cargo build
Updating registry `https://github.com/rust-lang/crates.io-index`
warning: spurious network error (2 tries remaining): [2/-1] failed to send request: A connection with the serve
r could not be established
warning: spurious network error (1 tries remaining): [2/-1] failed to send request: A connection with the server could not be established
error: failed to load source for a dependency on `rand`
Caused by:
Unable to update registry https://github.com/rust-lang/crates.io-index
Caused by:
failed to fetch `https://github.com/rust-lang/crates.io-index`
Caused by:
[2/-1] failed to send request: A connection with the server could not be established
Output with internet access. This takes some time and downloads 65MB of data for me:
C:\rust\guessing_game>cargo build
Updating registry `https://github.com/rust-lang/crates.io-index`
Downloading rand v0.3.16
Downloading libc v0.2.29
Compiling libc v0.2.29
Compiling rand v0.3.16
Compiling guessing_game v0.1.0 (file:///C:/rust/guessing_game)
Finished dev [unoptimized + debuginfo] target(s) in 4.35 secs
Use the crate in main.rs:
extern crate rand;
use std::io;
use std::cmp::Ordering;
use rand::Rng;
fn main() {
println!("Guess the number!");
let secret_number = rand::thread_rng().gen_range(1, 101);
loop {
println!("Please input your guess.");
let mut guess = String::new();
io::stdin()
.read_line(&mut guess)
.expect("Failed to read line");
let guess: u32 = match guess.trim().parse() {
Ok(num) => num,
Err(_) => continue,
};
println!("You guessed: {}", guess);
match guess.cmp(&secret_number) {
Ordering::Less => println!("Too small!"),
Ordering::Greater => println!("Too big!"),
Ordering::Equal => {
println!("You win!");
break;
}
}
}
}
Output:
C:\rust\guessing_game>cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
Running `target\debug\guessing_game.exe`
Guess the number!
Please input your guess.
50
You guessed: 50
Too small!
Please input your guess.
75
You guessed: 75
Too big!
Please input your guess.
60
You guessed: 60
Too big!
Please input your guess.
55
You guessed: 55
Too small!
Please input your guess.
57
You guessed: 57
You win!