STACK ADT

 A Stack is a linear data structure which follows Last In First Out (LIFO) principles,in which both insertion and deletion occur at only one end of the list called the 'Top'.

                                  

Operations on Stack:                                                                     The fundamental operations performed on stack are

1. Push
2. Pop 

1. Push :                                                                                                       

       The process of inserting a new element to the top of the stack. for every push operation the top is incremented by one.

                                                 

2. Pop:                                                                                                                                                                            

   The process of  deleting an element from the top of the stack is called  pop operation .after every pop operation the top pointer is decremented by 1.         

                                   

                                                                       

 Exceptional condition:                    

1. Overflow: Attempt to insert an element when the stack is full is said to be overflow.  
2. Underflow: Attempt to delete an element when the stack is empty is said to be underflow.

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