রাস্ট এক্সেপশন

fn user(name: &str) -> Result<&str, String> {
  if name == "" {
    return Err("ডেটা পাওয়া যায়নি".to_string());
  }

  Ok(name)
}

fn page() {
  match user("") {
    Ok(name) => println!("{}", name),
    Err(error) => println!("{}", error),
  }
}

fn main() {
  page();
}

use std::error::Error;
use std::fmt;

#[derive(Debug)]
struct UserError {
  message: String,
}

impl fmt::Display for UserError {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}", self.message)
  }
}

impl Error for UserError {}

fn user() -> Result<(), UserError> {
  Err(UserError {
    message: "ডেটা পাওয়া যায়নি".to_string(),
  })
}

fn page() {
  if let Err(error) = user() {
    println!("{}", error);
  }
}

fn main() {
  page();
}