// Introduction to Software Testing
// Authors: Paul Ammann & Jeff Offutt
// Chapter 5, section 5.2, page 189

class sum
{

//Effects: If x null throw NullPointerException
//   else return the sum of the values in x
public static int sum(int[] x)
{
   int s = 0;
   for (int i=0; i < x.length; i++)
   {
      s = s + x[i];
      // s = s - x[i];
   }
   return s;
}

public static void main (String []argv)
{  // Driver method for sum
   // Read an array from standard input, call sum()
   int []inArr = new int [argv.length];
   if (argv.length == 0)
   {
      System.out.println ("Usage: java numZero v1 [v2] [v3] ... ");
      return;
   }

   for (int i = 0; i< argv.length; i++)
   {
      try
      {
         inArr [i] = Integer.parseInt (argv[i]);
      }
      catch (NumberFormatException e)
      {
         System.out.println ("Entry must be a integer, using 1.");
         inArr [i] = 1;
      }
   }

   System.out.println ("The sum is: " + sum (inArr));
}

}