generics_and_traits.rs

use std::fmt;
use std::cmp::Ordering;

#[derive(Debug)]
struct Trade {
    shares: f64,
    price: f64
}

impl Trade {
    fn amount(&self) -> f64 {
        self.shares * self.price
    }    
}

impl fmt::Display for Trade {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f,"Trade{{ shares:{}, price:{}, amount:{} }}", 
            self.shares, self.price, self.amount())
    }
}

impl PartialOrd for Trade {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        self.amount().partial_cmp(&other.amount())
    }
}

impl PartialEq for Trade {
    fn eq(&self, other: &Self) -> bool {
        self.amount() == other.amount()
    }
}

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

    for item in list {
        if item > largest {
            largest = item;
        }
    }
    largest
}

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

    let result = largest::<i32>(&number_list);
    println!("The largest number is {}", result);

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

    let result = largest::<char>(&char_list);
    println!("The largest char is '{}'", result);
    
    let trades = vec![
    Trade {
        shares: 10.0,
        price: 15.50
    },
    Trade {
        shares: 5.0,
        price: 100.10
    }];
    
    let result = largest::<Trade>(&trades);
    println!("The largest Trade is {}", result);
    
}