fn main() {
    let v1 = vec![1, 2, 3];

    let v1_iter = v1.iter();

    for val in v1_iter {
        println!("Got: {}", val);
    }
}

#[cfg(test)]
mod tests {
    use std::mem::size_of_val;

    #[test]
    fn iterator_demonstration() {
        let v1 = vec![1, 2, 3];

        let mut v1_iter = v1.iter();

        assert_eq!(v1_iter.next(), Some(&1));
        assert_eq!(v1_iter.next(), Some(&1));
        assert_eq!(v1_iter.next(), Some(&1));
        assert_eq!(v1_iter.next(), None);
    }

    #[test]
    fn iterator_consumption() {
        let v1 = vec![1, 2, 3];

        let v1_iter = v1.iter();

        let s: i32 = v1_iter.sum();

        println!("{s}");

        assert_eq!(s, 6)
    }

    #[test]
    fn iterator_another_way_get() {
        let mut v1: Vec<u32> = vec![1, 2, 3];

        let v1_iter = v1.iter_mut();

        let res: Vec<&mut u32> = v1_iter
            .map(|x| {
                *x = *x * 3;
                x
            })
            .collect();

        println!("res: {:?}, sizeof: {}, addr : {:x}", res, size_of_val(&res), res.as_ptr() as usize);
        println!("v1: {:?}, sizeof: {}, addr: {:x}", v1, size_of_val(&v1), v1.as_ptr() as usize);

        assert!(false);
    }
}