// Introduction to Software Testing
// Authors: Paul Ammann & Jeff Offutt
// Chapter 5, section 5.2, page 191

class power
{

public static int power (int left, int right)
{
  //**************************************
  // Raises Left to the power of Right
  // precondition : Right >= 0
  // postcondition: Returns Left**Right
  //**************************************
   int rslt;
   rslt = left;
   if (right == 0)
   {
      rslt = 1;
   }
   else
   {
      for (int i = 2; i <= right; i++)
         rslt = rslt * left;
   }
   return (rslt);
}

public static void main (String []argv)
{  // Driver method for power
   // Read two integers from standard input, call power()
   int []inArr = new int [argv.length];
   if (argv.length != 2)
   {
      System.out.println ("Usage: java power v1 v2");
      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;
      }
   }
   if (inArr[1] < 0)
   {
       System.out.println("Right must be large or equal to 0, using 1.");
       inArr[1] = 1;
   }

   System.out.println ("The result is: " + power (inArr[0], inArr[1]));
}

}