80 lines
1.3 KiB
Rust
80 lines
1.3 KiB
Rust
// example on how to implement iterators
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struct VecIntoIter<T> {
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v: Vec<T>,
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len: usize,
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i: usize,
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}
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impl<T> VecIntoIter<T> {
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fn new(v: Vec<T>) -> Self {
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Self {
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len: v.len(),
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v,
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i: 0
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}
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}
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}
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struct VecIter<'a, T> {
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v: &'a Vec<T>,
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len: usize,
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i: usize,
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}
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impl<'a, T> VecIter<'a, T> {
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fn new(v: &'a Vec<T>) -> Self {
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Self {
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len: v.len(),
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v,
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i: 0
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}
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}
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}
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impl<'a, T> Iterator for VecIter<'a, T> {
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type Item = &'a T;
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fn next(&mut self) -> Option<Self::Item> {
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if self.i >= self.len {
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return None;
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}
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let n = self.i;
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self.i += 1;
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Some(&self.v[n])
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}
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}
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impl<T: Copy> Iterator for VecIntoIter<T> {
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type Item = T;
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fn next(&mut self) -> Option<Self::Item> {
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if self.i >= self.len {
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return None;
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}
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let n = self.i;
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self.i += 1;
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Some(self.v[n])
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}
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}
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fn main() {
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let v = vec![1, 2, 3];
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let mut it = VecIter::new(&v);
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while let Some(x) = it.next() {
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println!("{x}");
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}
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println!("{v:?}");
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let mut it = VecIntoIter::new(v);
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while let Some(x) = it.next() {
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println!("{x}");
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}
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// println!("{v:?}"); // v is consumed
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}
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