The Vec setSize(newSize) method should follow these steps:

• If mySize and newSize are different:
  1. If newSize is zero:
     1. Deallocate myArray;
     2. Set myArray to nullptr;
     3. Set mySize to zero.
  2. Otherwise:
     1. Allocate a new dynamic array of Items, storing its address in local variable newArray.
     2. If mySize is less than newSize:
        1. Copy mySize values from myArray into newArray.
        2. Set the remaining (newSize-mySize) values to zero.
        Otherwise, just copy newSize values from myArray into newArray.
     3. Set mySize to newSize.
     4. Deallocate myArray.
     5. Set myArray to newArray.