From 507355ec3b1066c707e19816b86ac1fb56fc0385 Mon Sep 17 00:00:00 2001
From: Dave Gauer <dave@ratfactor.com>
Date: Sat, 6 Feb 2021 15:54:56 -0500
Subject: [PATCH] Added ex. 37,38 structs

---
 37_structs.zig  | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
 38_structs2.zig | 53 ++++++++++++++++++++++++++++++++++++++++++++
 README.md       |  7 +++---
 ziglings        |  6 +++++
 4 files changed, 122 insertions(+), 3 deletions(-)
 create mode 100644 37_structs.zig
 create mode 100644 38_structs2.zig

diff --git a/37_structs.zig b/37_structs.zig
new file mode 100644
index 0000000..dd4b633
--- /dev/null
+++ b/37_structs.zig
@@ -0,0 +1,59 @@
+//
+// Being able to group values together lets us turn this:
+//
+//     point1_x = 3;
+//     point1_y = 16;
+//     point1_z = 27;
+//     point2_x = 7;
+//     point2_y = 13;
+//     point2_z = 34;
+//
+// into this:
+//
+//     point1 = Point{ .x=3, .y=16, .y=27 };
+//     point2 = Point{ .x=7, .y=13, .y=34 };
+//
+// The Point above is an example of a "struct" (short for "structure").
+// Here's how it could have been defined:
+//
+//     const Point = struct{ x: u32, y: u32, z: u32 };
+//
+// Let's store something fun with a struct: a roleplaying character!
+//
+const std = @import("std");
+
+// We'll use an enum to specify the character class.
+const Class = enum{
+    wizard,
+    thief,
+    bard,
+    warrior,
+};
+
+// Please add a new property to this struct called "health" and make
+// it a u8 integer type.
+const Character = struct{
+    class: Class,
+    gold: u32,
+    experience: u32,
+};
+
+pub fn main() void {
+    // Please initialize Glorp with 100 health.
+    var glorp_the_wise = Character{
+        .class      = Class.wizard,
+        .gold       = 20,
+        .experience = 10,
+    };
+
+    // Glorp gains some gold.
+    glorp_the_wise.gold += 5;
+
+    // Ouch! Glorp takes a punch!
+    glorp_the_wise.health -= 10;
+
+    std.debug.print("Your wizard has {} health and {} gold.", .{
+        glorp_the_wise.health,
+        glorp_the_wise.gold
+    });
+}
diff --git a/38_structs2.zig b/38_structs2.zig
new file mode 100644
index 0000000..9a67c25
--- /dev/null
+++ b/38_structs2.zig
@@ -0,0 +1,53 @@
+//
+// Grouping values in structs is not merely convenient. It also allows
+// us to treat the values as a single item when storing them, passing
+// them to functions, etc.
+// 
+// This exercise demonstrates how we can store structs in an array and
+// how doing so lets us print them all (both) using a loop.
+//
+const std = @import("std");
+
+const Class = enum{
+    wizard,
+    thief,
+    bard,
+    warrior,
+};
+
+const Character = struct{
+    class: Class,
+    gold: u32,
+    health: u8,
+    experience: u32,
+};
+
+pub fn main() void {
+    var chars: [2]Character = undefined;
+
+    // Glorp the Wise
+    chars[0] = Character{
+        .class      = Class.wizard,
+        .gold       = 20,
+        .health     = 100,
+        .experience = 10,
+    };
+
+    // Please add "Zump the Loud" with the following properties:
+    //
+    //     class      bard
+    //     gold       10
+    //     health     100
+    //     experience 20
+    //
+    // Feel free to run this program without adding Zump. What does
+    // it do and why?
+
+    // Printing all RPG characters in a loop:
+    for (chars) |c, num| {
+        std.debug.print("Character {} - G:{} H:{} XP:{}\n",
+                        .{num+1, c.gold, c.health, c.experience});
+    }
+
+    std.debug.print("\n", .{});
+}
diff --git a/README.md b/README.md
index be0b269..61d02fb 100644
--- a/README.md
+++ b/README.md
@@ -11,9 +11,10 @@ project for the [Rust](https://www.rust-lang.org/) language.
 
 ## Intended Audience
 
-This will probably be quite difficult if you've _never_ programmed before.
-However, no specific programming experience is required. And in particular,
-you are _not_ expected to know C or other "systems programming" language.
+This will probably be difficult if you've _never_ programmed before.
+But no specific programming experience is required. And in particular,
+you are _not_ expected to have any prior experience with "systems programming"
+or a "systems" level language such as C.
 
 Each exercise is self-contained and self-explained. However, you're encouraged
 to also check out these Zig language resources for more detail:
diff --git a/ziglings b/ziglings
index 93b6819..b328b81 100755
--- a/ziglings
+++ b/ziglings
@@ -68,6 +68,10 @@ function check_it {
     fi
 }
 
+# I've chosen to explicitly number AND list each exercise rather than rely
+# on sorting. Though it does mean manually renaming things to remove/insert,
+# it's worked out well so far because its explicit and foolproof.
+
 check_it 01_hello.zig "Hello world" "Note the error: the source file has a hint for fixing 'main'."
 check_it 02_std.zig "Standard Library"
 check_it 03_assignment.zig "55 314159 -11" "There are three mistakes in this one!"
@@ -104,6 +108,8 @@ check_it 33_iferror.zig "2<4. 3<4. 4=4. 5>4. 6>4." "Seriously, what's the deal w
 check_it 34_quiz4.zig "my_num=42" "Can you make this work?"
 check_it 35_enums.zig "1 2 3 9 8 7" "This problem seems familiar..."
 check_it 36_enums2.zig "#0000ff" "I'm feeling blue about this."
+check_it 37_structs.zig "Your wizard has 90 health and 25 gold."
+check_it 38_structs2.zig "Character 2 - G:10 H:100 XP:20"
 
 echo
 echo "    __   __          _ "