(a)
class Stack
{
    private int size = 0; 
    private object[] values = new object[10];
    ...
}

(b)
class Stack
{
    private int size = 0; 
    private object[] values = new object[10];
    public Stack(): base() {
    }
    ...
}

Example 5: (a) This code omits a constructor, and is equivalent to (b), which includes an explicit constructor.