ServiceController.ps1

# Define an array of services
$services = 'service1','service2','service3','service4'

# Iterate through each item in the array
foreach ($service in $services) {
    # Get the service and save it to the variable
    $serviceObj = Get-Service -Name $service
    
    # if the variable is present - An If statement returns a bool value
    if ($serviceObj) {
        # Stop the service
        Stop-Service -Name $serviceObj
    }
    else {
        "Service can not be stopped"
    }
}

# Reverses the order of the array
[array]::reverse($services)

# Iterate through the reversed services array stopping the services
foreach ($service in $services) {
    $serviceObj = Get-Service -Name $service
    
    if ($serviceObj) {
        Stop-Service -Name $service
    }
}

# Declare function which can be loaded into session
function Stop-AppServices {
    [cmdletbinding()]
    Param (
        [Parameter(Mandatory = $true,
            Position = 0)]
        [string[]]
        $service
    )
    
    foreach ($item in $services) {
        try {
            $serviceObj = Get-Service -Name $item -ErrorAction Stop
            
            if ($serviceObj) {
                Stop-Service -Name $service
            }
        }
        catch {
            throw $_.exception.message
        }
    }
}

# Usage of the function
Stop-AppServices -Service $serviceArr