AP计算机教程6-8：简单多选题

Which index is the last element in an array called nums at?

Which of the following declarations will cause a compile time error?

What is returned from arr[3] if arr={6, 3, 1, 2}?

What is returned from mystery when it is passed {10, 30, 30, 60}?

public static double mystery(int[] arr)
{
   double output = 0;
   for (int i = 0; i < arr.length; i++)
   {
      output = output + arr[i];
   }
   return output / arr.length;
}

Given the following values of a and the method doubleLast what will the values of a be after you execute: doubleLast()?

private int[ ] a = {-10, -5, 1, 4, 8, 30};

public void doubleLast()
{

   for (int i = a.length / 2; i < a.length; i++)
   {
      a[i] = a[i] * 2;
   }
}