Stacks - Linear Data Structure

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Introduction - 

          Stack is an ordered collection of data items. It is a last in, first out (LIFO) abstract data type and linear data structure. In stack new items can be added and removed only at the top. Stack is similar to a pile of dishes where dishes can be added at the top and dish coming last would be removed first.

Remark - So, stack is a linear data structure where items are added or removed at one end only.

      Figure - Stack

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Operations on Stack - 

                There are basically two primitive operations that can be carried out on a stack -

Push - Push operation is used to add a new node to the top of the stack.

Figure -  Push operation on Stack

Pop - Pop operation is used to remove an existing node from the top of the stack. 

Figure - Pop operation on Stack

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Uses of Stacks - 

• Stacks are used for evaluating Arithmetic expressions (and other sorts of expression).
• Generally used for implementing function or method calls.
• Implementing Recursion.
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