Deck Shuffling

Implemented a deck shuffling algorithm. It will iterate over the deck of
cards 1000 times and swap the card it is on with another random card to
mix up the deck.

Reviewed-on: #12

src/deck.rs

@@ -1,4 +1,5 @@
 use super::card::Card;
+use rand::random_range;
 
 pub struct Deck {
     deck_size: u64,
@@ -9,7 +10,7 @@ pub struct Deck {
 impl Deck {
     pub fn new(num_decks: u64) -> Self {
         let deck_size: u64 = num_decks * 52;
-        let mut cards: Vec<Card> = Vec::new();
+        let mut cards: Vec<Card> = Vec::with_capacity(deck_size as usize);
 
         for card in 0..deck_size {
             let value = (card % 13) as u8;
@@ -38,4 +39,19 @@ impl Deck {
     pub fn deck_size(&self) -> usize {
         self.deck_size as usize
     }
+
+    pub fn cur_card(&self) -> u64 {
+        self.current_card
+    }
+
+    pub fn shuffle(&mut self) {
+        for _ in 0..1000 {
+            for card in 0..self.deck_size {
+                let swap_card = random_range(0..self.deck_size);
+                let save_card = self.cards[card as usize];
+                self.cards[card as usize] = self.cards[swap_card as usize];
+                self.cards[swap_card as usize] = save_card;
+            }
+        }
+    }
 }