About Stacks

Data Structure and Algorithms Course
Practice Problems on Stack
Recent articles on Stack

Stack is a linear data structure which follows a particular order in which the operations are performed. The order may be LIFO(Last In First Out) or FILO(First In Last Out).

There are many real-life examples of a stack. Consider an example of plates stacked over one another in the canteen. The plate which is at the top is the first one to be removed, i.e. the plate which has been placed at the bottommost position remains in the stack for the longest period of time. So, it can be simply seen to follow LIFO(Last In First Out)/FILO(First In Last Out) order.

Basic Operations on Stack

In order to make manipulations in a stack, there are certain operations provided to us.

push() to insert an element into the stack
pop() to remove an element from the stack
top() Returns the top element of the stack.
isEmpty() returns true is stack is empty else false
size() returns the size of stack

Visual Representation of how Expressions Are Converted

1) Infix to Postfix
2) Infix to Prefix
3) Postfix evaluationx

Enter Valid Infix Expression

There the string is traversed in opposite direction

Enter Valid Postfix Expression

Whenever a Operator occurs 2 operands are popped and evaluated

Answer:-

Stack Trace

Applications of the stack:

Infix to Postfix /Prefix conversion
Redo-undo features at many places like editors, photoshop.
Forward and backward features in web browsers
Used in many algorithms like Tower of Hanoi, tree traversals, stock span problems, and histogram problems.
Backtracking is one of the algorithm designing techniques. Some examples of backtracking are the Knight-Tour problem, N-Queen problem, find your way through a maze, and game-like chess or checkers in all these problems we dive into someway if that way is not efficient we come back to the previous state and go into some another path. To get back from a current state we need to store the previous state for that purpose we need a stack.
In Graph Algorithms like Topological Sorting and Strongly Connected Components
In Memory management, any modern computer uses a stack as the primary management for a running purpose. Each program that is running in a computer system has its own memory allocations
String reversal is also another application of stack. Here one by one each character gets inserted into the stack. So the first character of the string is on the bottom of the stack and the last element of a string is on the top of the stack. After Performing the pop operations on the stack we get a string in reverse order.