Zig: completed Grains

zig/grains/.exercism/config.json

@@ -0,0 +1,22 @@
+{
+  "authors": [
+    "massivelivefun"
+  ],
+  "contributors": [
+    "ee7"
+  ],
+  "files": {
+    "solution": [
+      "grains.zig"
+    ],
+    "test": [
+      "test_grains.zig"
+    ],
+    "example": [
+      ".meta/example.zig"
+    ]
+  },
+  "blurb": "Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.",
+  "source": "The CodeRanch Cattle Drive, Assignment 6",
+  "source_url": "https://coderanch.com/wiki/718824/Grains"
+}

zig/grains/.exercism/metadata.json

@@ -0,0 +1 @@
+{"track":"zig","exercise":"grains","id":"04039904d0414848b219497a9a412373","url":"https://exercism.org/tracks/zig/exercises/grains","handle":"Chomp1295","is_requester":true,"auto_approve":false}

zig/grains/HELP.md

@@ -0,0 +1,53 @@
+# Help
+
+## Running the tests
+
+Write your code in `<exercise_name>.zig`.
+
+To run the tests for an exercise, run:
+
+```bash
+zig test test_exercise_name.zig
+```
+
+in the exercise's root directory (replacing `exercise_name` with the name of the exercise).
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit grains.zig` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Zig track's documentation](https://exercism.org/docs/tracks/zig)
+- The [Zig track's programming category on the forum](https://forum.exercism.org/c/programming/zig)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+- [The Zig Programming Language Documentation][documentation] is a great overview of all of the language features that Zig provides to those who use it.
+- [Zig Guide][zig-guide] is an excellent primer that explains the language features that Zig has to offer.
+- [Ziglings][ziglings] is highly recommended.
+  Learn Zig by fixing tiny broken programs.
+- [The Zig Programming Language Discord][discord-zig] is the main [Discord][discord].
+  It provides a great way to get in touch with the Zig community at large, and get some quick, direct help for any Zig related problem.
+- [#zig][irc] on irc.freenode.net is the main Zig IRC channel.
+- [/r/Zig][reddit] is the main Zig subreddit.
+- [Stack Overflow][stack-overflow] can be used to discover code snippets and solutions to problems that may have already asked and maybe solved by others.
+
+[discord]: https://discordapp.com
+[discord-zig]: https://discord.com/invite/gxsFFjE
+[documentation]: https://ziglang.org/documentation/master
+[irc]: https://webchat.freenode.net/?channels=%23zig
+[reddit]: https://www.reddit.com/r/Zig
+[stack-overflow]: https://stackoverflow.com/questions/tagged/zig
+[zig-guide]: https://zig.guide/
+[ziglings]: https://codeberg.org/ziglings/exercises

zig/grains/README.md

@@ -0,0 +1,34 @@
+# Grains
+
+Welcome to Grains on Exercism's Zig Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
+
+There once was a wise servant who saved the life of a prince.
+The king promised to pay whatever the servant could dream up.
+Knowing that the king loved chess, the servant told the king he would like to have grains of wheat.
+One grain on the first square of a chess board, with the number of grains doubling on each successive square.
+
+There are 64 squares on a chessboard (where square 1 has one grain, square 2 has two grains, and so on).
+
+Write code that shows:
+
+- how many grains were on a given square, and
+- the total number of grains on the chessboard
+
+## Source
+
+### Created by
+
+- @massivelivefun
+
+### Contributed to by
+
+- @ee7
+
+### Based on
+
+The CodeRanch Cattle Drive, Assignment 6 - https://coderanch.com/wiki/718824/Grains

zig/grains/grains.zig

@@ -0,0 +1,13 @@
+const std = @import("std");
+
+pub const ChessboardError = error{IndexOutOfBounds};
+
+pub fn square(index: usize) ChessboardError!u64 {
+    if (index > 64 or index < 1) return error.IndexOutOfBounds;
+
+    return std.math.pow(u64, 2, index - 1);
+}
+
+pub fn total() u64 {
+    return std.math.maxInt(u64);
+}

zig/grains/test_grains.zig

@@ -0,0 +1,65 @@
+const std = @import("std");
+const testing = std.testing;
+
+const grains = @import("grains.zig");
+const ChessboardError = grains.ChessboardError;
+
+test "grains on square 1" {
+    const expected: u64 = 1;
+    const actual = try grains.square(1);
+    try testing.expectEqual(expected, actual);
+}
+
+test "grains on square 2" {
+    const expected: u64 = 2;
+    const actual = try grains.square(2);
+    try testing.expectEqual(expected, actual);
+}
+
+test "grains on square 3" {
+    const expected: u64 = 4;
+    const actual = try grains.square(3);
+    try testing.expectEqual(expected, actual);
+}
+
+test "grains on square 4" {
+    const expected: u64 = 8;
+    const actual = try grains.square(4);
+    try testing.expectEqual(expected, actual);
+}
+
+test "grains on square 16" {
+    const expected: u64 = 32_768;
+    const actual = try grains.square(16);
+    try testing.expectEqual(expected, actual);
+}
+
+test "grains on square 32" {
+    const expected: u64 = 2_147_483_648;
+    const actual = try grains.square(32);
+    try testing.expectEqual(expected, actual);
+}
+
+test "grains on square 64" {
+    const expected: u64 = 9_223_372_036_854_775_808;
+    const actual = try grains.square(64);
+    try testing.expectEqual(expected, actual);
+}
+
+test "square 0 produces an error" {
+    const expected = ChessboardError.IndexOutOfBounds;
+    const actual = grains.square(0);
+    try testing.expectError(expected, actual);
+}
+
+test "square greater than 64 produces an error" {
+    const expected = ChessboardError.IndexOutOfBounds;
+    const actual = grains.square(65);
+    try testing.expectError(expected, actual);
+}
+
+test "returns the total number of grains on the board" {
+    const expected: u64 = 18_446_744_073_709_551_615;
+    const actual = grains.total();
+    try testing.expectEqual(expected, actual);
+}