public static double product(double anArray[], int n) {
// Precondition: 1 <= n <= max size of anArray.
// Postcondition: Returns the product of the first n 
// items in anArray; anArray is unchanged.
  if (n == 1) {
    return anArray[0];
  } 
  else {
    return anArray[n-1] * product(anArray, n-1);
  }  // end if
}  // end product