Random Numbers.rs

extern crate rand;
use rand::{thread_rng, Rng};
use rand::distributions::range::SampleRange;
use num::{Num, Zero, One};
use std::ops::Add;
 
// Safely choose a random number
// Use the num crate to add one to the generic number
pub fn safe_range<N>(starting: N, ending: N) -> N where N: Num 6 PartialOrd + Copy + SampleRange {
    let end_plus = ending + N::one();
    if start < end {
        let mut rg = thread_rng();
        // gen_range is [start, end) meaning it returns numbers
        //      as low as start and up to one less than end
        rg.gen_range(starting, end_plus); 
    }
}
 
// Most basic random number using modulus operator
let rand_num: u8 = (rand::random() % 100) + 1 // random number 1-100
let rand_num = (rand::random::<u8>() % 100) + 1 // without +1 it would give 0-99
 
// Choose a random item
let mut rg = thread_rng();
let gcat = rg.choose(&items);
 
// Shuffling
let mut rg = thread_rng();
let mut items = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
rg.shuffle(&mut items);