implement Modifier

go/dnd-character/.exercism/config.json

@@ -0,0 +1,21 @@
+{
+  "authors": ["jesse-kroon"],
+  "contributors": ["andrerfcsantos"],
+  "files": {
+    "solution": [
+      "dnd_character.go"
+    ],
+    "test": [
+      "dnd_character_test.go"
+    ],
+    "editor": [
+      "cases_test.go"
+    ],
+    "example": [
+      ".meta/example.go"
+    ]
+  },
+  "blurb": "Randomly generate Dungeons & Dragons characters.",
+  "source": "Simon Shine, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/616#issuecomment-437358945"
+}

go/dnd-character/.exercism/metadata.json

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+{"track":"go","exercise":"dnd-character","id":"717a81ad216c4bc59e90d083c5d10517","url":"https://exercism.org/tracks/go/exercises/dnd-character","handle":"rootulp","is_requester":true,"auto_approve":false}

go/dnd-character/HELP.md

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+# Help
+
+## Running the tests
+
+To run the tests run the command `go test` from within the exercise directory.
+
+If the test suite contains benchmarks, you can run these with the `--bench` and `--benchmem`
+flags:
+
+    go test -v --bench . --benchmem
+
+Keep in mind that each reviewer will run benchmarks on a different machine, with
+different specs, so the results from these benchmark tests may vary.
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit dnd_character.go` 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 [Go track's documentation](https://exercism.org/docs/tracks/go)
+- The [Go track's programming category on the forum](https://forum.exercism.org/c/programming/go)
+- [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.
+
+To get help if you're having trouble, you can use one of the following resources:
+
+- [How to Write Go Code](https://golang.org/doc/code.html)
+- [Effective Go](https://golang.org/doc/effective_go.html)
+- [Go Resources](http://golang.org/help)
+- [StackOverflow](http://stackoverflow.com/questions/tagged/go)

go/dnd-character/README.md

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+# D&D Character
+
+Welcome to D&D Character on Exercism's Go Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Introduction
+
+After weeks of anticipation, you and your friends get together for your very first game of [Dungeons & Dragons][dnd] (D&D).
+Since this is the first session of the game, each player has to generate a character to play with.
+The character's abilities are determined by rolling 6-sided dice, but where _are_ the dice?
+With a shock, you realize that your friends are waiting for _you_ to produce the dice; after all it was your idea to play D&D!
+Panicking, you realize you forgot to bring the dice, which would mean no D&D game.
+As you have some basic coding skills, you quickly come up with a solution: you'll write a program to simulate dice rolls.
+
+[dnd]: https://en.wikipedia.org/wiki/Dungeons_%26_Dragons
+
+## Instructions
+
+For a game of [Dungeons & Dragons][dnd], each player starts by generating a character they can play with.
+This character has, among other things, six abilities; strength, dexterity, constitution, intelligence, wisdom and charisma.
+These six abilities have scores that are determined randomly.
+You do this by rolling four 6-sided dice and recording the sum of the largest three dice.
+You do this six times, once for each ability.
+
+Your character's initial hitpoints are 10 + your character's constitution modifier.
+You find your character's constitution modifier by subtracting 10 from your character's constitution, divide by 2 and round down.
+
+Write a random character generator that follows the above rules.
+
+For example, the six throws of four dice may look like:
+
+- 5, 3, 1, 6: You discard the 1 and sum 5 + 3 + 6 = 14, which you assign to strength.
+- 3, 2, 5, 3: You discard the 2 and sum 3 + 5 + 3 = 11, which you assign to dexterity.
+- 1, 1, 1, 1: You discard the 1 and sum 1 + 1 + 1 = 3, which you assign to constitution.
+- 2, 1, 6, 6: You discard the 1 and sum 2 + 6 + 6 = 14, which you assign to intelligence.
+- 3, 5, 3, 4: You discard the 3 and sum 5 + 3 + 4 = 12, which you assign to wisdom.
+- 6, 6, 6, 6: You discard the 6 and sum 6 + 6 + 6 = 18, which you assign to charisma.
+
+Because constitution is 3, the constitution modifier is -4 and the hitpoints are 6.
+
+~~~~exercism/note
+Most programming languages feature (pseudo-)random generators, but few programming languages are designed to roll dice.
+One such language is [Troll][troll].
+
+[troll]: https://di.ku.dk/Ansatte/?pure=da%2Fpublications%2Ftroll-a-language-for-specifying-dicerolls(84a45ff0-068b-11df-825d-000ea68e967b)%2Fexport.html
+~~~~
+
+[dnd]: https://en.wikipedia.org/wiki/Dungeons_%26_Dragons
+
+## Source
+
+### Created by
+
+- @jesse-kroon
+
+### Contributed to by
+
+- @andrerfcsantos
+
+### Based on
+
+Simon Shine, Erik Schierboom - https://github.com/exercism/problem-specifications/issues/616#issuecomment-437358945

go/dnd-character/cases_test.go

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+package dndcharacter
+
+// This is an auto-generated file. Do not change it manually. Run the generator to update the file.
+// See https://github.com/exercism/go#synchronizing-tests-and-instructions
+// Source: exercism/problem-specifications
+// Commit: 02209d7 Reimplement test case in DnD Character (#2338)
+
+type modifierTestInput struct {
+	Score int
+}
+
+var modifierTests = []struct {
+	description string
+	input       modifierTestInput
+	expected    int
+}{
+
+	{
+		description: "ability modifier for score 3 is -4",
+		input: modifierTestInput{
+			Score: 3,
+		},
+		expected: -4,
+	},
+
+	{
+		description: "ability modifier for score 4 is -3",
+		input: modifierTestInput{
+			Score: 4,
+		},
+		expected: -3,
+	},
+
+	{
+		description: "ability modifier for score 5 is -3",
+		input: modifierTestInput{
+			Score: 5,
+		},
+		expected: -3,
+	},
+
+	{
+		description: "ability modifier for score 6 is -2",
+		input: modifierTestInput{
+			Score: 6,
+		},
+		expected: -2,
+	},
+
+	{
+		description: "ability modifier for score 7 is -2",
+		input: modifierTestInput{
+			Score: 7,
+		},
+		expected: -2,
+	},
+
+	{
+		description: "ability modifier for score 8 is -1",
+		input: modifierTestInput{
+			Score: 8,
+		},
+		expected: -1,
+	},
+
+	{
+		description: "ability modifier for score 9 is -1",
+		input: modifierTestInput{
+			Score: 9,
+		},
+		expected: -1,
+	},
+
+	{
+		description: "ability modifier for score 10 is 0",
+		input: modifierTestInput{
+			Score: 10,
+		},
+		expected: 0,
+	},
+
+	{
+		description: "ability modifier for score 11 is 0",
+		input: modifierTestInput{
+			Score: 11,
+		},
+		expected: 0,
+	},
+
+	{
+		description: "ability modifier for score 12 is +1",
+		input: modifierTestInput{
+			Score: 12,
+		},
+		expected: 1,
+	},
+
+	{
+		description: "ability modifier for score 13 is +1",
+		input: modifierTestInput{
+			Score: 13,
+		},
+		expected: 1,
+	},
+
+	{
+		description: "ability modifier for score 14 is +2",
+		input: modifierTestInput{
+			Score: 14,
+		},
+		expected: 2,
+	},
+
+	{
+		description: "ability modifier for score 15 is +2",
+		input: modifierTestInput{
+			Score: 15,
+		},
+		expected: 2,
+	},
+
+	{
+		description: "ability modifier for score 16 is +3",
+		input: modifierTestInput{
+			Score: 16,
+		},
+		expected: 3,
+	},
+
+	{
+		description: "ability modifier for score 17 is +3",
+		input: modifierTestInput{
+			Score: 17,
+		},
+		expected: 3,
+	},
+
+	{
+		description: "ability modifier for score 18 is +4",
+		input: modifierTestInput{
+			Score: 18,
+		},
+		expected: 4,
+	},
+}

go/dnd-character/dnd_character.go

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+package dndcharacter
+
+import "math"
+
+type Character struct {
+	Strength     int
+	Dexterity    int
+	Constitution int
+	Intelligence int
+	Wisdom       int
+	Charisma     int
+	Hitpoints    int
+}
+
+// Modifier calculates the ability modifier for a given ability score
+func Modifier(score int) int {
+	return int(math.Floor(float64(score-10) / 2))
+}
+
+// Ability uses randomness to generate the score for an ability
+func Ability() int {
+	panic("Please implement the Ability() function")
+}
+
+// GenerateCharacter creates a new Character with random scores for abilities
+func GenerateCharacter() Character {
+	panic("Please implement the GenerateCharacter() function")
+}

go/dnd-character/dnd_character_test.go

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+package dndcharacter
+
+import "testing"
+
+func TestModifier(t *testing.T) {
+	for _, tc := range modifierTests {
+		t.Run(tc.description, func(t *testing.T) {
+			actual := Modifier(tc.input.Score)
+			if actual != tc.expected {
+				t.Fatalf("Modifier(%d) = %d, want %d", tc.input.Score, actual, tc.expected)
+			}
+		})
+	}
+}
+
+func TestAbility(t *testing.T) {
+	t.Run("should generate ability score within accepted range", func(t *testing.T) {
+		for i := 0; i < 1000; i++ {
+			got := Ability()
+			if !inAcceptedRange(got) {
+				t.Fatalf("Ability() returned a score for an ability outside the accepted range. Got %d, expected a value between 3 and 18 inclusive.", got)
+			}
+		}
+	})
+}
+
+func TestGenerateCharacter(t *testing.T) {
+	t.Run("should generate a character with random ability scores", func(t *testing.T) {
+		for i := 0; i < 1000; i++ {
+			character := GenerateCharacter()
+
+			assertCharacterAbilityScoreInRange(t, "Charisma", character.Charisma)
+			assertCharacterAbilityScoreInRange(t, "Strength", character.Strength)
+			assertCharacterAbilityScoreInRange(t, "Dexterity", character.Dexterity)
+			assertCharacterAbilityScoreInRange(t, "Wisdom", character.Wisdom)
+			assertCharacterAbilityScoreInRange(t, "Intelligence", character.Intelligence)
+			assertCharacterAbilityScoreInRange(t, "Constitution", character.Constitution)
+
+			expectedHitpoints := 10 + Modifier(character.Constitution)
+			if character.Hitpoints != expectedHitpoints {
+				t.Fatalf("Got %d hitpoints for a character with %d constitution, expected %d hitpoints", character.Hitpoints, character.Constitution, expectedHitpoints)
+			}
+		}
+	})
+}
+
+func inAcceptedRange(score int) bool {
+	return score >= 3 && score <= 18
+}
+
+func assertCharacterAbilityScoreInRange(t *testing.T, ability string, score int) {
+	t.Helper()
+
+	if !inAcceptedRange(score) {
+		t.Fatalf("GenerateCharacter() created a character with a %s score of %d, but the score for an ability is expected to be between 3 and 18 inclusive", ability, score)
+	}
+}
+
+func BenchmarkModifier(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Modifier(i)
+	}
+}
+
+func BenchmarkAbility(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Ability()
+	}
+}
+
+func BenchmarkCharacter(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		GenerateCharacter()
+	}
+}

go/dnd-character/go.mod

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+module dnd-character
+
+go 1.18