Function Create-MyFoldler
{
	Param([string]$rootPath= $(throw"$rootPath required."), [string]$subFolder)

	if ([System.String]::IsNullOrEmpty($subFolder))
	{
		$folderToCreate=$rootPath
        write-host "Output 1:-" + $folderToCreate
	}
	else
	{
		$folderToCreate=Join-Path$rootPath$subFolder
        write-host "Output 2:-" + $folderToCreate
	}
	
    if (![IO.Directory]::Exists($folderToCreate)) 
	{
		New-Item $folderToCreate -ItemType directory
        write-host "Output 3:-" + $folderToCreate
	}
}


Create-MyFoldler -rootPath "c:\test"