diff --git a/lib/obp60task/code_size.ps1 b/lib/obp60task/code_size.ps1
index 0cf586b..3c1a0c7 100644
--- a/lib/obp60task/code_size.ps1
+++ b/lib/obp60task/code_size.ps1
@@ -1,12 +1,16 @@
-param([string]$dir = ".")
+param(
+    [string]$dir = "."
+)
 
 $total = 0
 
-Get-ChildItem $dir -Recurse -Include *.c, *.cpp, *.h -File | ForEach-Object {
-    $lines = [System.IO.File]::ReadLines($_.FullName).Count
+Get-ChildItem -Path $dir -Recurse -File | Where-Object {
+    $_.Extension -in ".c", ".cpp", ".h"
+} | ForEach-Object {
+    $lines = [System.Linq.Enumerable]::Count([System.IO.File]::ReadLines($_.FullName))
     Write-Output "$($_.FullName) : $lines"
     $total += $lines
 }
 
-Write-Output "-----------------------"
+Write-Output "-----------------------------"
 Write-Output "Over all files: $total"
\ No newline at end of file