card:default: implemented defaults for every card type

src/card/default.rs

@@ -0,0 +1,25 @@
+use crate::card::{Card, PlayingCard, Rank, Suit};
+
+impl Default for Rank {
+    fn default() -> Self {
+        Self::Three
+    }
+}
+
+impl Default for Suit {
+    fn default() -> Self {
+        Self::Diamond
+    }
+}
+
+impl Default for PlayingCard {
+    fn default() -> Self {
+        Self::new(0, Rank::default(), Suit::default())
+    }
+}
+
+impl Default for Card {
+    fn default() -> Self {
+        Self::PlayingCard(PlayingCard::default())
+    }
+}

src/card/mod.rs

@@ -1,3 +1,4 @@
+mod default;
 mod display;
 mod hash;
 mod impls;
@@ -41,10 +42,3 @@ pub enum Card {
     Joker(i64),
     PlayingCard(PlayingCard),
 }
-
-/** Given a sequence of Playing Cards, check if they are all of the same rank.
- */
-pub fn all_same_rank(cards: &[PlayingCard]) -> bool {
-    let rank = cards[0].rank;
-    cards[1..].iter().all(|card| rank == card.rank)
-}