Code shared from the Rust Playground

playground.rs

#[derive( PartialEq, Debug, Clone, Default)]
pub struct Thing {
    name: String,
    number: i32,
} 

impl Thing {
    fn new(name: &str, number: Option<i32>) -> Thing {
         Thing {
                 name: name.to_string(),
                 number: number.unwrap_or_default(),
          }
    }
}

fn main() 
{
    let mut thing_vector = vec![];
    thing_vector.push(Thing::new("John Doe", Some(37)));
    thing_vector.push(Thing::new("Jill Doe", None));
    
    for pl in &mut thing_vector {
        println!("{} {}", pl.name, pl.number);
    }
}