Fixed a few problems

README.md

@@ -2,4 +2,9 @@
 
 # zigdeck
 
-A non-functioning library that shuffles a deck of cards and deals them out
+A library that creates and shuffles a deck of cards from which you can draw
+
+The code builds but it's not yet complete.
+
+Tested with the the development version of [zig](https://ziglang.org/) (may
+not build with the last release).

src/root.zig

@@ -1,45 +1,45 @@
 const std = @import("std");
 
-const Card = struct {
-    suit: Suit,
-    value: u4,
-};
-
 const Suit = enum {
     Clubs,
     Diamonds,
     Hearts,
     Spades,
 };
 
+const Card = struct {
+    suit: Suit,
+    value: u4,
+};
+
 const Deck = struct {
     cards: [52]Card,
     top: usize,
 
     pub fn init() Deck {
         var deck: Deck = .{ .cards = undefined, .top = 0 };
         var i: usize = 0;
-        for (Suit) |suit| {
+        // inline for (std.meta.fields(Suit)) |suit| {
+        for (0..4) |suit| {
             for (0..13) |value| {
-                deck.cards[i] = Card{ .suit = suit, .value = value + 1 };
+                // std.debug.print("{d}\n", .{value});
+                deck.cards[i] = Card{ .suit = @enumFromInt(suit), .value = @as(u4, @intCast(value)) + 1 };
                 i += 1;
             }
         }
         return deck;
     }
 
-    pub fn shuffle(deck: *Deck) void {
-        var rng = std.rand.DefaultPrng.seed(@intCast(u64, std.time.milliTimestamp()));
-        for (deck.cards.enumerate()) |item| {
-            const i = item.index;
-            const j = rng.random().int(usize) % deck.cards.len;
+    pub fn shuffle(deck: *Deck, rng: *const std.rand.Random) void {
+        for (deck.cards, 0..) |_, item| {
+            const i = item;
+            const j = rng.int(usize) % deck.cards.len;
             const temp = deck.cards[i];
             deck.cards[i] = deck.cards[j];
             deck.cards[j] = temp;
         }
     }
 
-
     pub fn getTopCard(deck: *Deck) ?Card {
         if (deck.top >= deck.cards.len) return null;
         const card = deck.cards[deck.top];
@@ -50,7 +50,22 @@ const Deck = struct {
 
 test "Deck operations" {
     var deck = Deck.init();
-    Deck.shuffle(&deck);
+    try std.testing.expectEqual(Suit.Clubs, deck.cards[0].suit);
+    try std.testing.expectEqual(1, deck.cards[0].value);
+    try std.testing.expectEqual(Suit.Clubs, deck.cards[1].suit);
+    try std.testing.expectEqual(2, deck.cards[1].value);
+    try std.testing.expectEqual(Suit.Diamonds, deck.cards[13].suit);
+    try std.testing.expectEqual(1, deck.cards[13].value);
+    try std.testing.expectEqual(Suit.Hearts, deck.cards[26].suit);
+    try std.testing.expectEqual(1, deck.cards[26].value);
+    try std.testing.expectEqual(Suit.Spades, deck.cards[48].suit);
+    try std.testing.expectEqual(13, deck.cards[51].value);
+
+    // var rng = std.rand.DefaultPrng.init(@as(u64, @intCast(std.time.milliTimestamp())));
+    var rng = std.rand.DefaultPrng.init(1);
+    Deck.shuffle(&deck, &rng.random());
     const card = Deck.getTopCard(&deck) orelse return;
+    try std.testing.expectEqual(Suit.Clubs, card.suit);
+    try std.testing.expectEqual(12, card.value);
     std.debug.print("Top card: Suit = {}, Value = {}\n", .{ card.suit, card.value });
 }