largest_trait.rs

use std::cmp::PartialOrd;

fn largest<T: PartialOrd + Copy>(list: &[T]) -> T {
    let mut largest = list[0];

    for &item in list.iter() {
        if item > largest {
            largest = item;
        }
    }

    largest
}

fn main() {
    let numbers = vec![34, 50, 25, 100, 65];

    let result = largest(&numbers);
    println!("The largest number is {}", result);

    let chars = vec!['y', 'm', 'a', 'q'];

    let result = largest(&chars);
    println!("The largest char is {}", result);
}

// turned into

use std::cmp::PartialOrd;

fn largest<'a, T: PartialOrd>(list: &[T]) -> &T {
    let mut largest = list[0];

    for &item in list.iter() {
        if item > largest {
            largest = item;
        }
    }

    &largest
}

fn main() {
    let numbers = vec![34, 50, 25, 100, 65];

    let result = largest(&numbers);
    println!("The largest number is {}", result);

    let chars = vec!['y', 'm', 'a', 'q'];

    let result = largest(&chars);
    println!("The largest char is {}", result);

    let strings = vec!["foo".to_string(), "bar".to_string(), "baz".to_string()];

    let result = largest(&strings);
    println!("The largest string is {}", result);
}