pizza_party.rs

use std::io;
use std::io::Write;
use std::str::FromStr;

fn prompt<F>(question: &str) -> Result<F, F::Err>
    where F: FromStr
{
    let mut answer = String::new();
    print!("{} ", question);
    let _ = io::stdout().flush();
    let _ = io::stdin().read_line(&mut answer);
    answer.trim().to_string().parse::<F>()
}

fn main() {
    let people: u8 = prompt("How many people?").unwrap();
    let pizzas: u8 = prompt("How many pizzas?").unwrap();
    let slices_per_pizza = 8;
    let total_slices = pizzas * slices_per_pizza;
    let slices_per_person = total_slices / people;
    let leftovers = total_slices % people;

    println!("{} people with {} pizzas", people, pizzas);
    println!("Each person gets {} slices of pizza", slices_per_person);
    println!("There are {} leftover pieces", leftovers);
}