Add Prime Number in PowerShell (#4735)

Author: rzuckerm

archive/p/powershell/PrimeNumber.ps1

@@ -0,0 +1,35 @@
+function Show-Usage() {
+    Write-Host "Usage: please input a non-negative integer"
+    Exit 1
+}
+
+function Test-IsPrime([int]$Value) {
+    if ($Value -lt 2 -or ($Value -ne 2 -and $Value % 2 -eq 0)) {
+        return $false
+    }
+
+    $Q = [Math]::Floor([Math]::Sqrt($Value))
+    for ($X = 3; $X -le $Q; $X += 2) {
+        if ($Value % $X -eq 0) {
+            return $false
+        }
+    }
+
+    $true
+}
+
+if ($args.Length -lt 1) {
+    Show-Usage
+}
+
+try {
+    $Value = [int]::Parse($args[0])
+} catch {
+    Show-Usage
+}
+
+if ($Value -lt 0) {
+    Show-Usage
+}
+
+Write-Host ((Test-IsPrime $Value) ? "prime" : "composite")