pub struct FamilyIterator {
    offset: usize,
    family: Family,
}

impl Iterator for FamilyIterator {
    type Item = Person;

    fn next(&mut self) -> Option<Person> {
        let result = match self.offset {
            0 => self.family.a,
            1 => self.family.b,
            2 => self.family.c,
            _ => return None,
        };
        self.offset += 1;
        Some(result)
    }
}

impl IntoIterator for Family {
    type Item = Person ;
    type IntoIter = FamilyIterator;

    fn into_iter(self) -> Self::IntoIter {
        FamilyIterator {
            offset: 0,
            family: self,
        }
    }
}

pub struct Person {
 value: usize,
}

pub struct Family {
    a: Person,
    b: Person,
    c: Person,
}



fn main() {
    println!("Hello, world!");
    let family = Family{a: Person{value: 0}, b: Person{value: 1}, c: Person{value: 2}};

    for person in family {
        println!("Person's value: {}", person.value);
    }
}