added MonteCarlo in PowerShell (#760)

contents/monte_carlo_integration/code/powershell/MonteCarlo.ps1

@@ -0,0 +1,21 @@
+function Is-InCircle($x, $y, $radius=1) {
+    return ([Math]::Pow($x, 2) + [Math]::Pow($y, 2)) -lt [Math]::Pow($radius, 2)
+}
+
+function Monte-Carlo([int]$n) {
+    $PiCount = 0;
+    for ($i = 0; $i -lt $n; $i++) {
+        $x = Get-Random -Minimum 0.0 -Maximum 1.0
+        $y = Get-Random -Minimum 0.0 -Maximum 1.0
+
+        if (Is-InCircle $x $y) {
+            $PiCount++
+        }
+    }
+    return 4.0 * $PiCount / $n
+}
+
+# This could take some time
+$PiEstimate = Monte-Carlo 10000000
+Write-Host "The pi estimate is: $PiEstimate"
+Write-Host "Percent error is: $(100 * [Math]::Abs($PiEstimate - ([Math]::PI)) / ([Math]::PI))"

contents/monte_carlo_integration/monte_carlo_integration.md

@@ -99,6 +99,8 @@ each point is tested to see whether it's in the circle or not:
 </p>
 {% sample lang="coco" %}
 [import:4-9, lang:"coconut"](code/coconut/monte_carlo.coco)
+{% sample lang="ps1" %}
+[import:1-3, lang:"powershell"](code/powershell/MonteCarlo.ps1)
 {% endmethod %}
 
 If it's in the circle, we increase an internal count by one, and in the end,
@@ -206,6 +208,8 @@ The code snippets were taken from this [scratch project](https://scratch.mit.edu
 </p>
 {% sample lang="coco" %}
 [import, lang:"coconut"](code/coconut/monte_carlo.coco)
+{% sample lang="ps1" %}
+[import, lang:"powershell"](code/powershell/MonteCarlo.ps1)
 {% endmethod %}
 
 <script>