Stacks: Ordered, Flexible, and Efficient
Stacks, like arrays, are ordered collections of similar data types. Interestingly, stacks can be implemented using an array as the underlying data structure, although they are flexible enough to be implemented using other structures like linked lists.
The Core Operations: Push and Pop
When it comes to stacks, two operations reign supreme:
- Push: The act of inserting an element onto the stack.
- Pop: The act of removing an element from the stack.
The Cafeteria Analogy
Imagine a stack like a stack of trays in a cafeteria. Just like you would place a tray or plate at the top of the stack, the push operation places an element at the top of the stack. When it's time to clean up, you would remove the tray from the top, similar to how the pop operation removes the last-added element from the stack.
This behavior makes a stack a Last In, First Out (LIFO) data structure. The last element you put in is the first one you take out.
A Practical Example: Pushing an Element
Let's visualize pushing an element onto a stack. When we push the element 10, it becomes the bottom-most item in the stack, as shown below:
In this "box," you'll see the number 10 sitting at the bottom, signifying its place as the last-added (and currently only) element in the stack.