A stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle. It means that the most recently added element is the first one to be removed. The stack operates with two main operations: push, which adds an element to the top of the stack, and pop, which removes the top element from the stack.A stack can be implemented using an array or linked list. In both cases, a variable called top is used to keep track of the index or pointer to the top element of the stack.When pushing an element into the stack, the top variable is incremented, and the element is inserted at the new top position. When popping an element, the top variable is decremented, and the element at the current top position is removed.Stacks are commonly used in various computer algorithms and programming languages. They are particularly useful for tasks like function call management, expression evaluation, and backtracking. Additionally, stacks can be used to reverse the order of a sequence of elements.