File I/O - Rust Programming

Standard-library file functions write and read text. The example writes a number, reads it back, and parses it.

Program

Play the program to round-trip a number through a temporary file.

file_io.rs

use std::fs;

fn main() {
    let path = std::env::temp_dir().join(format!("egtry_rust_{}.txt", std::process::id()));
    fs::write(&path, "42\n").unwrap();
    let contents = fs::read_to_string(&path).unwrap();
    let number: i32 = contents.trim().parse().unwrap();
    fs::remove_file(&path).unwrap();
    println!("{}", number * 2);
}

fs::write `fs::write` saves text to a file path.

read_to_string `fs::read_to_string` loads the file back as text.

parse `trim().parse()` converts the text to a number.