class Exercise5
{
  // returns index of maximum element in array a 
  // of non-negative integers (-1, if a is empty)
  public static int maximum(int[] a)
  {
    int n = a.length;
    if (n == 0) 
      return -1;
    else
    {
      int p = 0;
      int m = 0;
      int i = 0;
      while (i < n)
      {
        if (a[i] > m)
        {
          p = i;
          m = a[i];
        }
        i = i+1;
      }
      return p;
    }
  }
}