How can I read a single line from stdin in Rust?

Question

I'm asking for the equivalent of fgets() in C.

let line = ...;
println!("You entered: {}", line);

I've read How to read user input in Rust?, but it asks how to read multiple lines; I want only one line.

I also read How do I read a single String from standard input?, but I'm not sure if it behaves like fgets() or sscanf("%s",...).

Answer 1

In How to read user input in Rust? you can see how to iterate over all lines:

use std::io::{self, BufRead};

fn main() {
    let stdin = io::stdin();
    for line in stdin.lock().lines() {
        println!("{}", line.unwrap());
    }
}

You can also manually iterate without a for-loop:

use std::io::{self, BufRead};

fn main() {
    let stdin = io::stdin();
    let mut iterator = stdin.lock().lines();
    let line1 = iterator.next().unwrap().unwrap();
    let line2 = iterator.next().unwrap().unwrap();
}

You cannot write a one-liner to do what you want. But the following reads a single line (and is exactly the same answer as in How do I read a single String from standard input?):

use std::io::{self, BufRead};

fn main() {
    let stdin = io::stdin();
    let line1 = stdin.lock().lines().next().unwrap().unwrap();
}

---

You can also use the text_io crate for super simple input:

#[macro_use] extern crate text_io;

fn main() {
    // reads until a \n is encountered
    let line: String = read!("{}\n");
}