Add armstrong numbers (#171)

config.json

@@ -50,6 +50,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "armstrong-numbers",
+        "name": "Armstrong Numbers",
+        "uuid": "7ee5d442-dbed-4831-aee1-3d58070dcc36",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "binary-search",
         "name": "Binary Search",

exercises/practice/armstrong-numbers/.docs/instructions.md

@@ -0,0 +1,14 @@
+# Instructions
+
+An [Armstrong number][armstrong-number] is a number that is the sum of its own digits each raised to the power of the number of digits.
+
+For example:
+
+- 9 is an Armstrong number, because `9 = 9^1 = 9`
+- 10 is _not_ an Armstrong number, because `10 != 1^2 + 0^2 = 1`
+- 153 is an Armstrong number, because: `153 = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153`
+- 154 is _not_ an Armstrong number, because: `154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190`
+
+Write some code to determine whether a number is an Armstrong number.
+
+[armstrong-number]: https://en.wikipedia.org/wiki/Narcissistic_number

exercises/practice/armstrong-numbers/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "armstrong-numbers.red"
+    ],
+    "test": [
+      "armstrong-numbers-test.red"
+    ],
+    "example": [
+      ".meta/example.red"
+    ]
+  },
+  "blurb": "Determine if a number is an Armstrong number.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Narcissistic_number"
+}

exercises/practice/armstrong-numbers/.meta/example.red

@@ -0,0 +1,16 @@
+Red [
+	description: {"Armstrong Numbers" exercise solution for exercism platform}
+	author: "BNAndras"
+]
+
+is-armstrong-number: function [
+	number
+] [
+	working: 0
+	digits: to-string number
+	foreach digit digits [
+		working: working + power to-integer form digit length? digits
+	]
+	working == number
+]
+

exercises/practice/armstrong-numbers/.meta/tests.toml

@@ -0,0 +1,45 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[c1ed103c-258d-45b2-be73-d8c6d9580c7b]
+description = "Zero is an Armstrong number"
+
+[579e8f03-9659-4b85-a1a2-d64350f6b17a]
+description = "Single-digit numbers are Armstrong numbers"
+
+[2d6db9dc-5bf8-4976-a90b-b2c2b9feba60]
+description = "There are no two-digit Armstrong numbers"
+
+[509c087f-e327-4113-a7d2-26a4e9d18283]
+description = "Three-digit number that is an Armstrong number"
+
+[7154547d-c2ce-468d-b214-4cb953b870cf]
+description = "Three-digit number that is not an Armstrong number"
+
+[6bac5b7b-42e9-4ecb-a8b0-4832229aa103]
+description = "Four-digit number that is an Armstrong number"
+
+[eed4b331-af80-45b5-a80b-19c9ea444b2e]
+description = "Four-digit number that is not an Armstrong number"
+
+[f971ced7-8d68-4758-aea1-d4194900b864]
+description = "Seven-digit number that is an Armstrong number"
+
+[7ee45d52-5d35-4fbd-b6f1-5c8cd8a67f18]
+description = "Seven-digit number that is not an Armstrong number"
+
+[5ee2fdf8-334e-4a46-bb8d-e5c19c02c148]
+description = "Armstrong number containing seven zeroes"
+include = false
+
+[12ffbf10-307a-434e-b4ad-c925680e1dd4]
+description = "The largest and last Armstrong number"
+include = false

exercises/practice/armstrong-numbers/armstrong-numbers-test.red

@@ -0,0 +1,96 @@
+Red [
+	description: {Tests for "Armstrong Numbers" Exercism exercise}
+	author: "loziniak"
+]
+
+#include %testlib.red
+
+test-init/limit %armstrong-numbers.red 1
+; test-init/limit %.meta/example.red 1						; test example solution
+
+canonical-cases: [#[
+    description: "Zero is an Armstrong number"
+    input: #[
+        number: 0
+    ]
+    expected: true
+    function: "is-armstrong-number"
+    uuid: "c1ed103c-258d-45b2-be73-d8c6d9580c7b"
+] #[
+    description: "Single-digit numbers are Armstrong numbers"
+    input: #[
+        number: 5
+    ]
+    expected: true
+    function: "is-armstrong-number"
+    uuid: "579e8f03-9659-4b85-a1a2-d64350f6b17a"
+] #[
+    description: "There are no two-digit Armstrong numbers"
+    input: #[
+        number: 10
+    ]
+    expected: false
+    function: "is-armstrong-number"
+    uuid: "2d6db9dc-5bf8-4976-a90b-b2c2b9feba60"
+] #[
+    description: "Three-digit number that is an Armstrong number"
+    input: #[
+        number: 153
+    ]
+    expected: true
+    function: "is-armstrong-number"
+    uuid: "509c087f-e327-4113-a7d2-26a4e9d18283"
+] #[
+    description: {Three-digit number that is not an Armstrong number}
+    input: #[
+        number: 100
+    ]
+    expected: false
+    function: "is-armstrong-number"
+    uuid: "7154547d-c2ce-468d-b214-4cb953b870cf"
+] #[
+    description: "Four-digit number that is an Armstrong number"
+    input: #[
+        number: 9474
+    ]
+    expected: true
+    function: "is-armstrong-number"
+    uuid: "6bac5b7b-42e9-4ecb-a8b0-4832229aa103"
+] #[
+    description: "Four-digit number that is not an Armstrong number"
+    input: #[
+        number: 9475
+    ]
+    expected: false
+    function: "is-armstrong-number"
+    uuid: "eed4b331-af80-45b5-a80b-19c9ea444b2e"
+] #[
+    description: "Seven-digit number that is an Armstrong number"
+    input: #[
+        number: 9926315
+    ]
+    expected: true
+    function: "is-armstrong-number"
+    uuid: "f971ced7-8d68-4758-aea1-d4194900b864"
+] #[
+    description: {Seven-digit number that is not an Armstrong number}
+    input: #[
+        number: 9926314
+    ]
+    expected: false
+    function: "is-armstrong-number"
+    uuid: "7ee45d52-5d35-4fbd-b6f1-5c8cd8a67f18"
+]]
+
+
+foreach c-case canonical-cases [
+	case-code: reduce [
+		'expect c-case/expected compose [
+			(to word! c-case/function) (values-of c-case/input)
+		] 
+	]
+
+	test c-case/description case-code
+]
+
+test-results/print

exercises/practice/armstrong-numbers/armstrong-numbers.red

@@ -0,0 +1,11 @@
+Red [
+	description: {"Armstrong Numbers" exercise solution for exercism platform}
+	author: "" ; you can write your name here, in quotes
+]
+
+is-armstrong-number: function [
+	number
+] [
+	cause-error 'user 'message "You need to implement is-armstrong-number function."
+]
+