The below PowerShell program will force the user to specify the value of the two variables by setting the Parameter attribute in a function to true.
function addition {
param([Parameter(Mandatory=$true)] $one, [Parameter(Mandatory=$true)] $two)
return ([int]$one + [int]$two)
}
If the user forgets to enter the value of both or either variable of the function then PowerShell will ask the user to enter them.
> addition
