52 lines
1.4 KiB
Rust
52 lines
1.4 KiB
Rust
// This function returns how much ice cream there is left in the fridge.
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// If it's before 22:00 (24-hour system), then 5 scoops are left. At 22:00,
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// someone eats it all, so no ice cream is left (value 0). Return `None` if
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// `hour_of_day` is higher than 23.
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fn maybe_ice_cream(hour_of_day: u16) -> Option<u16> {
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if hour_of_day > 23 {
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None
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} else if hour_of_day < 22 {
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Some(5)
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} else {
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Some(0)
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}
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// OR
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// fn maybe_ice_cream(hour_of_day: u16) -> Option<u16> {
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// match hour_of_day {
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// 0..=21 => Some(5),
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// 22 | 23 => Some(0),
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// _ => None,
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// }
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// }
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}
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fn main() {
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// You can optionally experiment here.
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn raw_value() {
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// TODO: Fix this test. How do you get the value contained in the
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// Option?
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let ice_creams = maybe_ice_cream(12);
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assert_eq!(ice_creams, Some(5)); // Don't change this line.
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}
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#[test]
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fn check_ice_cream() {
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assert_eq!(maybe_ice_cream(0), Some(5));
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assert_eq!(maybe_ice_cream(9), Some(5));
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assert_eq!(maybe_ice_cream(18), Some(5));
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assert_eq!(maybe_ice_cream(22), Some(0));
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assert_eq!(maybe_ice_cream(23), Some(0));
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assert_eq!(maybe_ice_cream(24), None);
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assert_eq!(maybe_ice_cream(25), None);
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}
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}
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