A stack is a list with the restriction that insertions and deletions can be performed in only one position. We call this behavior last in first out(LIFO), and the position, we call it top, top of a stack.
Those Pictures shows a stack can be.
It can be …
or It can be …
As we can see, The most recently inserted element can be examined prior to performing a Pop by use of Top routine.
Operation
Push
It easy to understand how to push a value into a stack.
Pop
It also easy to understand how to pop a value into a stack.
Implementation
Actually, stack still is a list, whatever a linkelist or arraylist, all of them can be the data structure of a stack.
In my version, I use the linkedlist as the data structure of it.
For better push of element, I make the head node points to the Top, and the last node of this linkedlist called Bottom. If we always insert or delete node at the index 0, we can get a stack.
