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// run-pass
use std::fmt::Debug;
use std::cmp::{self, PartialOrd, Ordering};
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
struct Foo {
n: u8,
name: &'static str
}
impl PartialOrd for Foo {
fn partial_cmp(&self, other: &Foo) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl Ord for Foo {
fn cmp(&self, other: &Foo) -> Ordering {
self.n.cmp(&other.n)
}
}
fn main() {
let a = Foo { n: 4, name: "a" };
let b = Foo { n: 4, name: "b" };
let c = Foo { n: 8, name: "c" };
let d = Foo { n: 8, name: "d" };
let e = Foo { n: 22, name: "e" };
let f = Foo { n: 22, name: "f" };
let data = [a, b, c, d, e, f];
// `min` should return the left when the values are equal
assert_eq!(data.iter().min(), Some(&a));
assert_eq!(data.iter().min_by_key(|a| a.n), Some(&a));
assert_eq!(cmp::min(a, b), a);
assert_eq!(cmp::min(b, a), b);
// `max` should return the right when the values are equal
assert_eq!(data.iter().max(), Some(&f));
assert_eq!(data.iter().max_by_key(|a| a.n), Some(&f));
assert_eq!(cmp::max(e, f), f);
assert_eq!(cmp::max(f, e), e);
let mut presorted = data.to_vec();
presorted.sort();
assert_stable(&presorted);
let mut presorted = data.to_vec();
presorted.sort_by(|a, b| a.cmp(b));
assert_stable(&presorted);
// Assert that sorted and min/max are the same
fn assert_stable<T: Ord + Debug>(presorted: &[T]) {
for slice in presorted.windows(2) {
let a = &slice[0];
let b = &slice[1];
assert_eq!(a, cmp::min(a, b));
assert_eq!(b, cmp::max(a, b));
}
}
}
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