Code shared from the Rust Playground

playground.rs

#![allow(unused)]
fn main() {
    let a = [1, 2, 3];
    
    let ref mut iter = a.into_iter();
    
    let sum: i32 = iter.take(2)
                       .fold(0, |acc, &i| acc + i );
    
    assert_eq!(sum, 3);
    
    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.next(), None);
}