Stack_Data_Structure.pptx

Stack_Data_Structure.pptx

• 1.
  STACK
• 2.
  DATA STRUCTURE LINEAR DATA STRUCTURE ARRAY QUEUESTACK NON LINEAR DATA STRUCTURE
• 3.
  What is LinearData Structure In linear data structure, data is arranged in linear sequence.  Data items can be traversed in a single run.  In linear data structure elements are accessed or placed in contiguous(together in sequence) memory location.
• 4.
  WHAT Is  Astack is called a last-in-first-out (LIFO) collection. This means that the last thing we added (pushed) is the first thing that gets pulled (popped) off. A stack is a sequence of items that are accessible at only one end of the sequence.
• 5.
  Definition of Stack: Stacksin Data Structures is a linear type of data structure that follows the LIFO (Last-In-First-Out) principle and allows insertion and deletion operations from one end of the stack data structure, that is top. If any Element inserted then Top will be increased by 1 & if any Element deleted then Top will be decreased by 1. Top=Top+1 (Insertion) Top=Top-1 (Deletion)
• 6.
  EXAMPLES OF STACK:
• 7.
  Operations that canbe performed on STACK:  PUSH.  POP.
• 8.
  PUSH : Itis used to insert items into the stack. POP: It is used to delete items from stack. TOP: It represents the current location of data in stack.
• 9.
  ALGORITHM OF INSERTIONIN STACK: (PUSH) 1. Insertion(a,top,item,max) 2. If top=max then print ‘STACK OVERFLOW’ exit else 3. top=top+1 end if 4. a[top]=item 5. Exit
• 10.
  ALGORITHM OF DELETIONIN STACK: (POP) 1. Deletion(a,top,item) 2. If top=0 then print ‘STACK UNDERFLOW’ exit else 3. item=a[top] end if 4 . top=top-1 5. Exit
• 11.
  ALGORITHM OF DISPLAYIN STACK: 1.Display(top,i,a[i]) 2.If top=0 then Print ‘STACK EMPTY’ Exit Else 3.For i=top to 0 Print a[i] End for 4.exit
• 12.
  APPLICATIONS OF STACKSARE: I. Reversing Strings: • A simple application of stack is reversing strings. To reverse a string , the characters of string are pushed onto the stack one by one as the string is read from left to right. • Once all the characters of string are pushed onto stack, they are popped one by one. Since the character last pushed in comes out first, subsequent pop operation results in the reversal of the string.
• 13.
  For example: To reversethe string ‘REVERSE’ the string is read from left to right and its characters are pushed . LIKE: onto a stack.
• 14.
  II. Checking thevalidity of an expression containing nested parenthesis: • Stacks are also used to check whether a given arithmetic expressions containing nested parenthesis is properly parenthesized. • The program for checking the validity of an expression verifies that for each left parenthesis braces or bracket ,there is a corresponding closing symbol and symbols are appropriately nested.
• 15.
  For example: VALID INPUTSINVALID INPUTS { } { ( } ( { [ ] } ) ( [ ( ( ) ] ) { [ ] ( ) } { } [ ] ) [ { ( { } [ ] ( { [ { ) } ( ] } ] })}]
• 16.
  III. Evaluating arithmeticexpressions: INFIX notation: The general way of writing arithmetic expressions is known as infix notation. e.g, (a+b) PREFIX notation: e.g, +AB POSTFIX notation: e.g: AB+
• 17.
  Conversion of INFIXto POSTFIX conversion: Example: 2+(4-1)*3 2+41-*3 2+41-3* 241-3*+ step1 step2 step3 step4
• 18.
  CURREN T SYMBOL ACTION PERFORME D STACK STATUS POSTFIX EXPRESSIO N (PUSH C C 2 2 2 + PUSH + (+ 2 ( PUSH ( (+( 24 4 24 - PUSH - (+(- 241 1 POP 241- ) (+ 241- * PUSH * (+* 241- 3 241-3 POP * 241-3* POP + 241-3*+ CONVERSION OF INFIX INTO POSTFIX 2+(4-1)*3 into 241-3*+
• 19.
  THANK YOU