1. DATA STRUCTURE Presented By: Mahmoud Rafeek Alfarra Using C# MINISTRY OF EDUCATION & HIGHER EDUCATION COLLEGE OF SCIENCE AND TECHNOLOGY KHANYOUNIS- PALESTINE Information Technology, 3’rd Semester Lecture 9 & 10: Stack

2. Outline  What is stack ?  What is the main Stack’s Operations?  Stack implementation  Stack’s application  Examples (discovering other operations)  Emank X Mezank !!

3. What is stack ?  A stack is a constrained version of a linked list.  A stack takes new nodes and releases nodes only at the top.  For this reason, a stack is referred to as a last-in, first-out (LIFO) data structure. 3 Presented & Prepared by: Mahmoud R. Alfarra

4. What is stack ?  We define a stack as a list of items that are accessible only from the end of the list, which is called the top of the stack. 4 Presented & Prepared by: Mahmoud R. Alfarra Top

5. What is the main Stack’s Operations? 5 Presented & Prepared by: Mahmoud R. Alfarra  The primary operations to manipulate a stack are push and pop.  The Push operation adds an item to the top of the stack.  The Pop operation removes item from the top of the stack.  The Peek operation just views the top item without actually removing it.

6. 6 Presented & Prepared by: Mahmoud R. Alfarra What is the main Stack’s Operations?

7. 7 Presented & Prepared by: Mahmoud R. Alfarra What is the main Stack’s Operations?

8. Stack implementation 8 Presented & Prepared by: Mahmoud R. Alfarra  We’ll implement the stack as a class, called CStack.  The items of this stack are objects of class list( car, table, …)  This means that, the implementation of stack as the linked list and differ just in the operations.

9. Stack’s application 9 Presented & Prepared by: Mahmoud R. Alfarra  Stacks have many interesting applications.  For example, when a program calls a method, the called method must know how to return to its caller, so the return address is pushed onto the program execution stack.  If a series of method calls occurs, the successive return values are pushed onto the stack in last-in, first-out order so that each method can return to its caller.

10. Stack’s application 10 Presented & Prepared by: Mahmoud R. Alfarra  Stacks support recursive method calls in the same manner that they do conventional non-recursive method calls.

11. Emank X Mezank !! أعظم أسبـاب النجاة استعن بالله

12. Next Lecture Examples (Discovering other operations)