33 lines
898 B
Rust
33 lines
898 B
Rust
// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![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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