Introduction to Stacks
Let’s go over the Stacks pattern, its real-world applications, and some problems we can solve with it.
About the pattern
A stack is a linear data structure that organizes and manages data in a Last In, First Out (LIFO) manner. This means the last element added to the stack is the first to be removed. Think of it like a stack of plates where you can only add or remove plates from the top.
There are two fundamental operations, push and pop, to add and remove elements while maintaining the LIFO order. Let’s delve into each operation:
push: This operation involves placing an element at the top of the stack. Whenever we push a new element onto the stack it becomes the new top element and this is why the stack grows in an upward direction.
pop: This operation involves removing the top element from the stack. The removed element is usually returned by the pop operation so that we can use or process it. After a pop operation, the element just below the one removed becomes the new top element.
The slides below are the visual demonstration of the push and pop operations:
There is some capacity associated with every stack which is nothing but the size of the stack. It is important to keep an eye on the stack’s capacity while performing the push and pop operations otherwise it results in either stack overflow or underflow.
A stack overflow occurs when we try to push an element onto a full stack. Therefore, a push operation can’t be called on a full stack. For example, if the stack has a capacity of
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