public void Push(T item)
{
while (_firstStack.Count > 0 &&
IsLessThan(_firstStack.Peek(), item))
{
_secondStack.Push(_firstStack.Pop());
}
_firstStack.Push(item);
while (_secondStack.Count > 0)
{
_firstStack.Push(_secondStack.Pop());
}
}
private void RearangeStacks()
{
while (_firstStack.Count != 0)
{
_secondStack.Push(_firstStack.Pop());
}
}
public void Should_Push_And_Pop_Correct_Order()
{
//arrange
var data = new int[] { 1, 2, 3 };
var stack = new MyLinkedListStack <int>();
//act
stack.Push(data[0]);
stack.Push(data[1]);
stack.Push(data[2]);
var first = stack.Pop();
var second = stack.Pop();
var third = stack.Pop();
//assert
first.ShouldBeEquivalentTo(data[2]);
second.ShouldBeEquivalentTo(data[1]);
third.ShouldBeEquivalentTo(data[0]);
}
public void Should_Pop_Throw_If_Stack_Is_Empty()
{
//arrange
var stack = new MyLinkedListStack <int>();
//act
Action act = () => stack.Pop();
//assert
act.ShouldThrow <InvalidOperationException>();
}
public T Dequeue()
{
if (Count == 0)
{
throw new InvalidOperationException();
}
if (_secondStack.Count == 0)
{
RearangeStacks();
}
return(_secondStack.Pop());
}
