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//! Counts the number of lines in a file given as an argument.
use std::env::args;
use async_std::fs::File;
use async_std::io::{self, BufReader};
use async_std::prelude::*;
use async_std::task;
fn main() -> io::Result<()> {
let path = args().nth(1).expect("missing path argument");
task::block_on(async {
let file = File::open(&path).await?;
let mut lines = BufReader::new(file).lines();
let mut count = 0u64;
while let Some(line) = lines.next().await {
line?;
count += 1;
}
println!("The file contains {} lines.", count);
Ok(())
})
}
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