Stack

Stack is a data structure which is based on the principle of Last In First Out (LIFO) which means that the last element that is put into the structure can only be taken out first. This structure is analogous to a stack of plates: on top of them you put new plates while to remove a plate you have to take the one which sits on top. Stack is one of the fundamental data structures in computer science and plays an important role in many algorithms and operations.

Key Characteristics of a Stack

1. ‍LIFO Principle: The key that identifies a stack is that operations are performed in a Last In, First Out (LIFO) style. This means that the newly inserted element is the first one to be deleted and so on this is called first-in-first-out. Queues on the other hand work in the first in, first out a system where the earliest element to be placed in the queue is the first to be removed while stacks work in reverse order.‍
2. Push and Pop Operations: Push: The process used in inserting a new element in the stack at the highest position in the stack. Each of the push operations leads to an increase in the size of the stack by one.‍
3. Pop: This operation was done to pop out the top element in the stack. Starting with pop operations, it should be noted that each of them reduces the stack size by one. Whereas if the stack is empty then a pop operation always leads to an underflow condition that no element can be deleted.‍
4. Top of the Stack: The top here means the last element that was pushed on the stack which will be the first to be popped from the stack. Only one element at the top is actually accessible for deletion and hence the LIFO principle is followed in this case.‍
5. Empty Stack: An empty stack is a stack on which no operation has been done for its push operation to insert an item under this stack. In such an instance, the top of the stack is essentially undefined and therefore if a pop operation is to be attempted then it leads to an error or underflow state.‍
6. Overflow and Underflow: 

• ‍Overflow: This is so when one wants to do a push operation often on the stack and discovers that the stack is of a limited size.‍
• Underflow: This is experienced when one tries to use pop operation on a stack which has no elements.

Common Use Cases for Stacks

1. ‍Function Call Management: Stack is employed for calling functions in the majority of the programming languages in use today. The Call stack or stack is used to store the information that is already active with subroutines or functions and their respective local variable. When a function is called it is recorded in the stack memories and when it is ‘finished’ the memory of that particular function is erased from the stack memories.‍
2. Expression Evaluation: They are used in the evaluation of arithmetic expressions among which the conversion of infix to postfix or prefix and the actual computation.‍
3. Backtracking: Stacks are used in backtracking algorithms and that’s why they are utilized in depth-first search of graphs or trees. This data structure helps record the path of the algorithm so that it moves backward to another path once it reaches a ‘dead-end’.‍
4. Undo Mechanism: Everyday applications like the common text editor employ stack in order to support the undo function. The state change for each action is descended to the stack and the last change is un-done by removing the stack’s top.‍
5. Parsing: It is also used more so in the parsing of expressions especially in the compilers and interpreters. They help in managing the structure of the source code in the form of nested expressions or statements in the form of a pyramid.

Advantages of Stacks

1. ‍Simple and Efficient: Stacks are very easy to implement and we get the best access time for the last come first served basis mode. When it comes to push and pop both those operations are \(O(1)\) and hence they are very fast.‍
2. Memory Management: Stacks are normally used in keeping track of memory during function calls and recursion just to name but a few since they help in the management of local variables and function state.
3. ‍Controlled Access: The Last-In-First-Out nature of the stacks also implies that access to data is well-managed and thus perfect when the order of operation is important.
4. ‍Supports Reversibility: Struct stack organizations arise in natural circumstances where reversing or the sequence of aspects is of importance in matters concerning algorithms and many others.

Disadvantages and Considerations

1. ‍Limited Access: Stacks are different from other data structures for example arrays or linked lists since in the structure only the top element is accessible. This limited access can be also a disadvantage during the work, where several elements should be read and modified at the one time.‍
2. Fixed Size Limitation: Some of the important points to note are: If a stack is implemented with a fixed size ( say an array to implement stack ) then this stack can overflow if too much data is pushed into this stack. This needs to be done with caution in order to prevent situations where data overflows hence giving wrong values.‍
3. Lack of Flexibility: There are issues which make the strict LIFO order of stacks not the most ideal to solve for. In any other cases like random access or accessing the elements on a First in First out basis, there are other data structures that are more suitable for the job such as queues or linked lists.‍
4. Risk of Underflow: In some cases when a program tries to delete an element from an empty stack it results in an underflow and thus may lead to error or crash down. There should be proper checks which should be put in place to avoid this.

Conclusion

In conclusion, a Stack is a data structure, that uses LIFO – Last In First Out technique or pattern in that the last element that was inserted is the first to be removed. Stacks are almost indispensable in different computing processes, such as service requests, computation of mathematical expressions, or backtracking. They afford ease, accuracy, and measured interaction which makes them an elementary resource in computing. However, their application is somewhat limited and may cause an overflow or underflow problem, if used in real-life applications that include large or dynamic sets, for instance.