[New Exercise]: Triangle

config.json

@@ -251,6 +251,16 @@
         "prerequisites": [],
         "difficulty": 1
       },
+      {
+        "slug": "triangle",
+        "name": "Triangle",
+        "uuid": "b439d97f-3661-45d4-903d-6c739e4ab05f",
+        "practices": [
+            "bools"
+        ],
+        "prerequisites": [],
+        "difficulty": 1
+      },
       {
         "slug": "etl",
         "name": "Etl",

exercises/practice/triangle/.docs/instructions.append.md

@@ -0,0 +1,20 @@
+# About Enum
+The enum statement allows you to create a strongly typed set of labels.
+You can use that enumeration in the code without having to parse or check for spelling errors.
+
+Enumerations are internally represented as integers with a starting value of zero.
+By default, PowerShell assigns the first label in the list the value zero, and assigns the remaining labels with consecutive integers.
+
+Example:
+```pwsh
+Enum Fruits {
+    APPLE       #default internal value 0
+    ORANGE      #default internal value 1
+    MANGO       #default internal value 2
+}
+
+$myFavFruit = [Fruits]::APPLE
+Write-host $myFavFruit => APPLE
+``````
+
+To know more about Enum in powershell please check out [Enum module.](https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_enum)

exercises/practice/triangle/.docs/instructions.md

@@ -0,0 +1,29 @@
+# Instructions
+
+Determine if a triangle is equilateral, isosceles, or scalene.
+
+An _equilateral_ triangle has all three sides the same length.
+
+An _isosceles_ triangle has at least two sides the same length.
+(It is sometimes specified as having exactly two sides the same length, but for the purposes of this exercise we'll say at least two.)
+
+A _scalene_ triangle has all sides of different lengths.
+
+## Note
+
+For a shape to be a triangle at all, all sides have to be of length > 0, and the sum of the lengths of any two sides must be greater than or equal to the length of the third side.
+
+In equations:
+
+Let `a`, `b`, and `c` be sides of the triangle.
+Then all three of the following expressions must be true:
+
+```text
+a + b ≥ c
+b + c ≥ a
+a + c ≥ b
+```
+
+See [Triangle Inequality][triangle-inequality]
+
+[triangle-inequality]: https://en.wikipedia.org/wiki/Triangle_inequality

exercises/practice/triangle/.meta/Triangle.example.ps1

@@ -0,0 +1,46 @@
+Enum Triangle {
+    EQUILATERAL
+    ISOSCELES
+    SCALENE
+}
+
+Function Get-Triangle() {
+    <#
+    .SYNOPSIS
+    Determine if a triangle is EQUILATERAL, ISOSCELES, or SCALENE.
+
+    .DESCRIPTION
+    Given 3 sides of a triangle, return the type of that triangle if it is a valid triangle.
+
+    .PARAMETER Sides
+    The lengths of a triangle's sides.
+
+    .EXAMPLE
+    Get-Triangle -Sides @(1,2,3)
+    #>
+
+    [CmdletBinding()]
+    Param (
+        [double[]]$Sides
+    )
+    Test-Validity $Sides
+    switch (($Sides | Select-Object -Unique).Count) {
+        1       { return [Triangle]::EQUILATERAL }
+        2       { return [Triangle]::ISOSCELES }
+        default { return [Triangle]::SCALENE }
+    }
+}
+
+Function Test-Validity() {
+    [CmdletBinding()]
+    Param (
+        [double[]]$Sides
+    )
+    if ($Sides | Where-Object {$_ -le 0}) {
+        Throw "All side lengths must be positive."
+    }
+    $sortedSides = $Sides | Sort-Object
+    if ($sortedSides[0] + $sortedSides[1] -lt $sortedSides[2]) {
+        Throw "Side lengths violate triangle inequality."
+    }
+}

exercises/practice/triangle/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": ["glaxxie"],
+  "files": {
+    "solution": [
+      "Triangle.ps1"
+    ],
+    "test": [
+      "Triangle.tests.ps1"
+    ],
+    "example": [
+      ".meta/Triangle.example.ps1"
+    ]
+  },
+  "blurb": "Determine if a triangle is equilateral, isosceles, or scalene.",
+  "source": "The Ruby Koans triangle project, parts 1 & 2",
+  "source_url": "https://web.archive.org/web/20220831105330/http://rubykoans.com"
+}

exercises/practice/triangle/.meta/tests.toml

@@ -0,0 +1,73 @@
+# 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.
+
+[8b2c43ac-7257-43f9-b552-7631a91988af]
+description = "equilateral triangle -> all sides are equal"
+
+[33eb6f87-0498-4ccf-9573-7f8c3ce92b7b]
+description = "equilateral triangle -> any side is unequal"
+
+[c6585b7d-a8c0-4ad8-8a34-e21d36f7ad87]
+description = "equilateral triangle -> no sides are equal"
+
+[16e8ceb0-eadb-46d1-b892-c50327479251]
+description = "equilateral triangle -> all zero sides is not a triangle"
+
+[3022f537-b8e5-4cc1-8f12-fd775827a00c]
+description = "equilateral triangle -> sides may be floats"
+
+[cbc612dc-d75a-4c1c-87fc-e2d5edd70b71]
+description = "isosceles triangle -> last two sides are equal"
+
+[e388ce93-f25e-4daf-b977-4b7ede992217]
+description = "isosceles triangle -> first two sides are equal"
+
+[d2080b79-4523-4c3f-9d42-2da6e81ab30f]
+description = "isosceles triangle -> first and last sides are equal"
+
+[8d71e185-2bd7-4841-b7e1-71689a5491d8]
+description = "isosceles triangle -> equilateral triangles are also isosceles"
+
+[840ed5f8-366f-43c5-ac69-8f05e6f10bbb]
+description = "isosceles triangle -> no sides are equal"
+
+[2eba0cfb-6c65-4c40-8146-30b608905eae]
+description = "isosceles triangle -> first triangle inequality violation"
+
+[278469cb-ac6b-41f0-81d4-66d9b828f8ac]
+description = "isosceles triangle -> second triangle inequality violation"
+
+[90efb0c7-72bb-4514-b320-3a3892e278ff]
+description = "isosceles triangle -> third triangle inequality violation"
+
+[adb4ee20-532f-43dc-8d31-e9271b7ef2bc]
+description = "isosceles triangle -> sides may be floats"
+
+[e8b5f09c-ec2e-47c1-abec-f35095733afb]
+description = "scalene triangle -> no sides are equal"
+
+[2510001f-b44d-4d18-9872-2303e7977dc1]
+description = "scalene triangle -> all sides are equal"
+
+[c6e15a92-90d9-4fb3-90a2-eef64f8d3e1e]
+description = "scalene triangle -> first and second sides are equal"
+
+[3da23a91-a166-419a-9abf-baf4868fd985]
+description = "scalene triangle -> first and third sides are equal"
+
+[b6a75d98-1fef-4c42-8e9a-9db854ba0a4d]
+description = "scalene triangle -> second and third sides are equal"
+
+[70ad5154-0033-48b7-af2c-b8d739cd9fdc]
+description = "scalene triangle -> may not violate triangle inequality"
+
+[26d9d59d-f8f1-40d3-ad58-ae4d54123d7d]
+description = "scalene triangle -> sides may be floats"

exercises/practice/triangle/Triangle.ps1

@@ -0,0 +1,22 @@
+Function Get-Triangle() {
+    <#
+    .SYNOPSIS
+    Determine if a triangle is equilateral, isosceles, or scalene.
+
+    .DESCRIPTION
+    Given 3 sides of a triangle, return the type of that triangle if it is a valid triangle.
+
+    .PARAMETER Sides
+    The lengths of a triangle's sides.
+
+    .EXAMPLE
+    Get-Triangle -Sides @(1,2,3)
+    Return: [Triangle]::SCALENE
+    #>
+
+    [CmdletBinding()]
+    Param (
+        [double[]]$Sides
+    )
+    Throw "Please implement this function"
+}

exercises/practice/triangle/Triangle.tests.ps1

@@ -0,0 +1,103 @@
+BeforeAll {
+    . "./Triangle.ps1"
+}
+
+Describe "Test Get-Triangle" {
+    Context "Passing Tests" {
+        It "equilateral all sides are equal" {
+            $got = Get-Triangle -Sides @(2, 2, 2)
+            $want = [Triangle]::EQUILATERAL
+
+            $got | Should -BeExactly $want
+        }
+
+        It "equilateral all sides are equal and float" {
+            $got = Get-Triangle -Sides @(0.5, 0.5, 0.5)
+            $want = [Triangle]::EQUILATERAL
+
+            $got | Should -BeExactly $want
+        }
+
+        It "isosceles first and last sides are equal" {
+            $got = Get-Triangle -Sides @(3, 4, 3)
+            $want = [Triangle]::ISOSCELES
+
+            $got | Should -BeExactly $want
+        }
+
+        It "isosceles first two sides are equal" {
+            $got = Get-Triangle -Sides @(4, 4, 3)
+            $want = [Triangle]::ISOSCELES
+
+            $got | Should -BeExactly $want
+        }
+
+        It "isosceles last two sides are equal" {
+            $got = Get-Triangle -Sides @(3, 4, 4)
+            $want = [Triangle]::ISOSCELES
+
+            $got | Should -BeExactly $want
+        }
+
+        It "isosceles two sides are equal and float" {
+            $got = Get-Triangle -Sides @(0.5, 0.5, 0.4)
+            $want = [Triangle]::ISOSCELES
+
+            $got | Should -BeExactly $want
+        }
+
+        It "isosceles two big equal sides" {
+            $got = Get-Triangle -Sides @(10, 10, 2)
+            $want = [Triangle]::ISOSCELES
+
+            $got | Should -BeExactly $want
+        }
+
+        It "scalene no sides are equal descending order" {
+            $got = Get-Triangle -Sides @(5, 4, 3)
+            $want = [Triangle]::SCALENE
+
+            $got | Should -BeExactly $want
+        }
+
+        It "scalene no sides are equal ascending order" {
+            $got = Get-Triangle -Sides @(4, 7, 11)
+            $want = [Triangle]::SCALENE
+
+            $got | Should -BeExactly $want
+        }
+
+        It "scalene sides are float" {
+            $got = Get-Triangle -Sides @(0.4, 0.3, 0.6)
+            $want = [Triangle]::SCALENE
+
+            $got | Should -BeExactly $want
+        }
+    }
+
+    Context "Invalid Inputs" {
+        It "all zero sides is not a triangle" {
+            { Get-Triangle -Sides @(0, 0, 0)} | Should -Throw "All side lengths must be positive."
+        }
+
+        It "negative sides are illegal" {
+            { Get-Triangle -Sides @(3, 4, -5)} | Should -Throw "All side lengths must be positive."
+        }
+
+        It "first isosceles triangle inequality violation" {
+            { Get-Triangle -Sides @(1, 1, 3)} | Should -Throw "Side lengths violate triangle inequality."
+        }
+
+        It "second isosceles triangle inequality violation" {
+            { Get-Triangle -Sides @(1, 3, 1)} | Should -Throw "Side lengths violate triangle inequality."
+        }
+
+        It "third isosceles triangle inequality violation" {
+            { Get-Triangle -Sides @(3, 1, 1)} | Should -Throw "Side lengths violate triangle inequality."
+        }
+
+        It "SCALENE triangle inequality violation" {
+            { Get-Triangle -Sides @(7, 3, 2)} | Should -Throw "Side lengths violate triangle inequality."
+        }
+    }
+}