#[derive(PartialEq, Eq, PartialOrd, Ord)]enumE {    Top,    Bottom,}assert!(E::Top < E::Bottom);

#[derive(PartialEq, Eq, PartialOrd, Ord)]enumE {    Top =2,    Bottom =1,}assert!(E::Bottom < E::Top);

usestd::cmp::Ordering;structCharacter {    health: u32,    experience: u32,    mana: f32,}implOrdforCharacter {fncmp(&self, other:&Self) -> Ordering {self.experience            .cmp(&other.experience)            .then(self.health.cmp(&other.health))    }}implPartialOrdforCharacter {fnpartial_cmp(&self, other:&Self) ->Option<Ordering> {Some(self.cmp(other))    }}implPartialEqforCharacter {fneq(&self, other:&Self) -> bool {self.health == other.health &&self.experience == other.experience    }}implEqforCharacter {}

usestd::cmp::Ordering;#[derive(Debug)]structCharacter {    health: f32,}implOrdforCharacter {fncmp(&self, other:&Self) -> std::cmp::Ordering {ifself.health < other.health {            Ordering::Less        }else ifself.health > other.health {            Ordering::Greater        }else{            Ordering::Equal        }    }}implPartialOrdforCharacter {fnpartial_cmp(&self, other:&Self) ->Option<Ordering> {Some(self.cmp(other))    }}implPartialEqforCharacter {fneq(&self, other:&Self) -> bool {self.health == other.health    }}implEqforCharacter {}leta = Character { health:4.5};letb = Character { health: f32::NAN };// Mistake: floating-point values do not form a total order and using the built-in comparison// operands to implement `Ord` irregardless of that reality does not change it. Use// `f32::total_cmp` if you need a total order for floating-point values.// Reflexivity requirement of `Ord` is not given.assert!(a == a);assert!(b != b);// Antisymmetry requirement of `Ord` is not given. Only one of a < c and c < a is allowed to be// true, not both or neither.assert_eq!((a < b)asu8 + (b < a)asu8,0);

usestd::cmp::Ordering;#[derive(Debug)]structCharacter {    health: u32,    experience: u32,}implPartialOrdforCharacter {fnpartial_cmp(&self, other:&Self) ->Option<Ordering> {Some(self.cmp(other))    }}implOrdforCharacter {fncmp(&self, other:&Self) -> std::cmp::Ordering {ifself.health <50{self.health.cmp(&other.health)        }else{self.experience.cmp(&other.experience)        }    }}// For performance reasons implementing `PartialEq` this way is not the idiomatic way, but it// ensures consistent behavior between `PartialEq`, `PartialOrd` and `Ord` in this example.implPartialEqforCharacter {fneq(&self, other:&Self) -> bool {self.cmp(other) == Ordering::Equal    }}implEqforCharacter {}leta = Character {    health:3,    experience:5,};letb = Character {    health:10,    experience:77,};letc = Character {    health:143,    experience:2,};// Mistake: The implementation of `Ord` compares different fields depending on the value of// `self.health`, the resulting order is not total.// Transitivity requirement of `Ord` is not given. If a is smaller than b and b is smaller than// c, by transitive property a must also be smaller than c.assert!(a < b && b < c && c < a);// Antisymmetry requirement of `Ord` is not given. Only one of a < c and c < a is allowed to be// true, not both or neither.assert_eq!((a < c)asu8 + (c < a)asu8,2);