# Stack Basics

• Stack is a data structure which follows LIFO i.e. Last-In-First-Out method.

• The data/element which is stored last in the stack i.e. the element at top will be accessed first.

• Insertion and deletion both take place at the top.

• Operations

  1. push() – Adding element to stack.
  2. pop() – removing element from stack.
  3. top() – to get the element at top.
  4. empty() – to check if the stack is empty or not.

• Applications

  1. Undo operation in text editors.
  2. Expression evaluation - evaluation of arithmatic expressions.
  3. Expression conversion – Infix , postfix & prefix.
  4. Recursion / Function calls.