diff --git a/exercises/12_options/options1.rs b/exercises/12_options/options1.rs index b7cf7b0b..5009f8b6 100644 --- a/exercises/12_options/options1.rs +++ b/exercises/12_options/options1.rs @@ -1,12 +1,9 @@ // This function returns how much icecream there is left in the fridge. -// If it's before 10PM, there's 5 scoops left. At 10PM, someone eats it -// all, so there'll be no more left :( -fn maybe_icecream(time_of_day: u16) -> Option { - // We use the 24-hour system here, so 10PM is a value of 22 and 12AM is a - // value of 0. The Option output should gracefully handle cases where - // time_of_day > 23. - // TODO: Complete the function body - remember to return an Option! - ??? +// If it's before 22:00 (24-hour system), then 5 scoops are left. At 22:00, +// someone eats it all, so no icecream is left (value 0). Return `None` if +// `hour_of_day` is higher than 23. +fn maybe_icecream(hour_of_day: u16) -> Option { + // TODO: Complete the function body. } fn main() { @@ -17,6 +14,14 @@ fn main() { mod tests { use super::*; + #[test] + fn raw_value() { + // TODO: Fix this test. How do you get the value contained in the + // Option? + let icecreams = maybe_icecream(12); + assert_eq!(icecreams, 5); + } + #[test] fn check_icecream() { assert_eq!(maybe_icecream(0), Some(5)); @@ -24,14 +29,7 @@ mod tests { assert_eq!(maybe_icecream(18), Some(5)); assert_eq!(maybe_icecream(22), Some(0)); assert_eq!(maybe_icecream(23), Some(0)); + assert_eq!(maybe_icecream(24), None); assert_eq!(maybe_icecream(25), None); } - - #[test] - fn raw_value() { - // TODO: Fix this test. How do you get at the value contained in the - // Option? - let icecreams = maybe_icecream(12); - assert_eq!(icecreams, 5); - } } diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml index c5ce8479..3694b94f 100644 --- a/rustlings-macros/info.toml +++ b/rustlings-macros/info.toml @@ -603,7 +603,7 @@ hint = """ Options can have a `Some` value, with an inner value, or a `None` value, without an inner value. -There's multiple ways to get at the inner value, you can use `unwrap`, or +There are multiple ways to get at the inner value, you can use `unwrap`, or pattern match. Unwrapping is the easiest, but how do you do it safely so that it doesn't panic in your face later?""" diff --git a/solutions/12_options/options1.rs b/solutions/12_options/options1.rs index 4e181989..1ffbb045 100644 --- a/solutions/12_options/options1.rs +++ b/solutions/12_options/options1.rs @@ -1 +1,38 @@ -// Solutions will be available before the stable release. Thank you for testing the beta version 🥰 +// This function returns how much icecream there is left in the fridge. +// If it's before 22:00 (24-hour system), then 5 scoops are left. At 22:00, +// someone eats it all, so no icecream is left (value 0). Return `None` if +// `hour_of_day` is higher than 23. +fn maybe_icecream(hour_of_day: u16) -> Option { + match hour_of_day { + 0..22 => Some(5), + 22..24 => Some(0), + _ => None, + } +} + +fn main() { + // You can optionally experiment here. +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn raw_value() { + // Using `unwrap` is fine in a test. + let icecreams = maybe_icecream(12).unwrap(); + assert_eq!(icecreams, 5); + } + + #[test] + fn check_icecream() { + assert_eq!(maybe_icecream(0), Some(5)); + assert_eq!(maybe_icecream(9), Some(5)); + assert_eq!(maybe_icecream(18), Some(5)); + assert_eq!(maybe_icecream(22), Some(0)); + assert_eq!(maybe_icecream(23), Some(0)); + assert_eq!(maybe_icecream(24), None); + assert_eq!(maybe_icecream(25), None); + } +}