// options2.rs // // Execute `rustlings hint options2` or use the `hint` watch subcommand for a // hint. mod tests { #[test] fn simple_option() { let target = "rustlings"; let optional_target = Some(target); if let Some(word) = optional_target { assert_eq!(word, target); } } #[test] fn layered_option() { let range = 10; let mut optional_integers: Vec> = vec![None]; for i in 1..(range + 1) { optional_integers.push(Some(i)); } let mut cursor = range; while let Some(Some(integer)) = optional_integers.pop() { assert_eq!(integer, cursor); cursor -= 1; if cursor == 0 { break; } } assert_eq!(cursor, 0); } }