repeat-char.rs

#!/usr/bin/env run-cargo-script
//
// Repeat same character
//

fn main() {
  println!("0: {}", (0..40).map(|_| "-").collect::<Vec<_>>().join(""));

  println!("1: {}", (0..40).map(|_| "-").collect::<String>());

  println!("2: {}", std::iter::repeat("-").take(40).collect::<String>());

  println!("3: {}", format!("{:-^1$}", "", 40));

  println!("4: {}", format!("{:-^40}", ""));

  println!("5: {:-^40}", "");

  println!("6: {}", vec!['-'; 40].iter().collect::<String>());

  println!("7: {}", vec!["-"; 40].concat());

  println!("8: {}", std::str::from_utf8(&[b'-'; 40]).unwrap());

  println!("9: {}", unsafe {
    &*(&[b'-'; 40] as *const [u8] as *const str) as &str
  });

  println!("A: {}", "-".repeat(40));

  // Does Rust keep length information across casts?
  let sv = unsafe {
    &*(&[b'-'; 40] as *const [u8] as *const str) as &str
  };
  println!("len={}", sv.len());
}