//
// program to sum integers from file, where filename is a command-line argument
//
// version that "catches" exceptions
//
if (args.length < 1) {
  println("need command-line argument (name of file)")
}
else {
  try {
    val source = scala.io.Source.fromFile(args(0))
    var sum = 0
    for (line <- source.getLines) {
      sum += line.toInt
    }
    source.close
    println("sum is " + sum)
  }
  catch {
    case e:java.io.FileNotFoundException => {
      println("could not open file:  " + e.getMessage)
    }
    case e:java.lang.NumberFormatException => {
      println("invalid input:  " + e.getMessage)
    }
  }
}