struct Count {
    pub value: u32,
    inter_value: u32,
}

impl Count {
    fn new(value: u32) -> Self {
        Self {
            value,
            inter_value: 0,
        }
    }
}

impl Iterator for Count {
    type Item = u32;

    fn next(&mut self) -> Option<Self::Item> {
        if self.inter_value < self.value {
            self.inter_value += 1;
            Some(self.inter_value)
        } else {
            None
        }
    }
}

fn main() {
    let counter = Count::new(5);
    counter.for_each(|v| println!("{}", v));
}