Implement new()

Source: https://rust-unofficial.github.io/patterns/idioms/ctor.html?highlight=construc#constructors

Rust's convention for constructing a new object is via new(). When you define your own type, implement new() that creates a new instance.

#![allow(unused)]
fn main() {
struct Ex {
    field1: i32,
    field2: i32,
}

impl Ex {
    fn new() -> Self {
        Ex {
            field1: 0,
            field2: 0,
        }
    }
}
}