What is a stack?

Here is a brief explanation of stack:

Plan B)

(Information gotten from http://interactivepython.org/)

The Stack Abstract Data Type

The stack abstract data type is defined by the following structure and operations. A stack is structured, as described above, as an ordered collection of items where items are added to and removed from the end called the “top.” Stacks are ordered LIFO. The stack operations are given below.

• Stack() creates a new stack that is empty. It needs no parameters and returns an empty stack.

• push(item) adds a new item to the top of the stack. It needs the item and returns nothing.

• pop() removes the top item from the stack. It needs no parameters and returns the item. The stack is modified.

• peek() returns the top item from the stack but does not remove it. It needs no parameters. The stack is not modified.

• isEmpty() tests to see whether the stack is empty. It needs no parameters and returns a boolean value.

• size() returns the number of items on the stack. It needs no parameters and returns an integer.

Stack examples:

A pile of boxes, where tou can only take the boxes from the above to get the ones at the bottom

In a pile of books you have to take the book at the top in order to take the next book.

References:

Brad Miller, David Ranum.. (2014). The Stack Abstract Data Type¶. 27 Maarzo del 2015, de http://interactivepython.org/ Sitio web: http://interactivepython.org/LpOMZ/courselib/static/pythonds/BasicDS/TheStackAbstractDataType.html

#stack