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24 lines
467 B
Rust
24 lines
467 B
Rust
#![warn(clippy::copy_iterator)]
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#[derive(Copy, Clone)]
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struct Countdown(u8);
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impl Iterator for Countdown {
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type Item = u8;
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fn next(&mut self) -> Option<u8> {
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self.0.checked_sub(1).map(|c| {
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self.0 = c;
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c
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})
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}
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}
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fn main() {
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let my_iterator = Countdown(5);
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let a: Vec<_> = my_iterator.take(1).collect();
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assert_eq!(a.len(), 1);
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let b: Vec<_> = my_iterator.collect();
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assert_eq!(b.len(), 5);
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}
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