Step 2


将下面的内容保存到项目的根目录(和 Cargo.toml 同一个目录),文件名 poem.txt

I'm nobody! Who are you?
Are you nobody, too?
Then there's a pair of us - don't tell!
They'd banish us, you know.

How dreary to be somebody!
How public, like a frog
To tell your name the livelong day
To an admiring bog!


导入 std::fs, 并使用 fs::read_to_string(filename) 读取文件内容,并打印出来。

运行 cargo run the poem.txt 测试一下,要能正确打印出文件的内容。

Step2 answer
use std::env;
use std::fs;

fn main() {
    // --snip--
    println!("In file {}", filename);

    let contents = fs::read_to_string(filename)
        .expect("Something went wrong reading the file");

    println!("With text:\n{}", contents);