小编web*_*tee的帖子

我想为IntoIterator包含a的结构实现trait String.迭代器基于chars()迭代器,应该计算'1'字符并累积结果.这是我到目前为止的简化版本:

use std::iter::Map;
use std::str::Chars;

fn main() {
    let str_struct = StringStruct { system_string: String::from("1101") };
    for a in str_struct {
        println!("{}", a);
    }
}

struct StringStruct {
    system_string: String
}

impl IntoIterator for StringStruct {
    type Item = u32;
    type IntoIter = Map<Chars, Fn(char) -> u32>;

    fn into_iter(self) -> Self::IntoIter {
        let count = 0;
        return self.system_string.chars().map(|c| match c {
            Some('1') => {
                count += 1;
                return Some(count);
            },
            Some(chr) => …