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use std::{env, error::Error, ffi::OsString, process};
fn run() -> Result<(), Box<dyn Error>> {
let file_path = get_first_arg()?;
let mut wtr = csv::Writer::from_path(file_path)?;
wtr.write_record(&[
"City",
"State",
"Population",
"Latitude",
"Longitude",
])?;
wtr.write_record(&[
"Davidsons Landing",
"AK",
"",
"65.2419444",
"-165.2716667",
])?;
wtr.write_record(&["Kenai", "AK", "7610", "60.5544444", "-151.2583333"])?;
wtr.write_record(&["Oakman", "AL", "", "33.7133333", "-87.3886111"])?;
wtr.flush()?;
Ok(())
}
/// Returns the first positional argument sent to this process. If there are no
/// positional arguments, then this returns an error.
fn get_first_arg() -> Result<OsString, Box<dyn Error>> {
match env::args_os().nth(1) {
None => Err(From::from("expected 1 argument, but got none")),
Some(file_path) => Ok(file_path),
}
}
fn main() {
if let Err(err) = run() {
println!("{}", err);
process::exit(1);
}
}
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