Data structure by Digvijay
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This document discusses stacks, which are non-linear data structures that follow the LIFO (last in, first out) principle. Stacks have operations like push and pop that insert and remove elements from the top of the stack. Pushing adds an element and increments the top pointer, while popping removes an element and decrements the top pointer. Stacks have applications in expression evaluation, memory management, and recursion. The document provides algorithms and code examples for implementing push and pop operations on a stack.
![ALGORITHM FOR PUSH
OPERATIONITEM, TOP)
PUSH(MAXSTK,
STEP 1: If TOP = MAXSTK THEN [Stack already
filled?]
Print "OVERFLOW"
Go to step 4
End if
STEP 2: TOP = TOP + 1 [Increase TOP by 1]
STEP 3: Set STK[TOP] = ITEM [Insert ITEM in
new TOP position]](https://image.slidesharecdn.com/datastructuredigvijay2ndyearii-sem2-140108063033-phpapp02/85/Data-structure-by-Digvijay-8-320.jpg)
![Program implementation of PUSH
operation
void push()
{ int item;
If(TOP==maxsize-1)
{ printf(“n Stack is full”);
getch();
exit(0);
}
else
{ printf(“n Enter the element to be inserted”);
scanf(“%d”, &item);
TOP=TOP+1;
stack[TOP]=item;
}
}](https://image.slidesharecdn.com/datastructuredigvijay2ndyearii-sem2-140108063033-phpapp02/85/Data-structure-by-Digvijay-9-320.jpg)
![ALGORITHM FOR POP
OPERATION
POP[STACK,TOP,ITEM]
STEP 1: If TOP=0
Print ”Underflow”
STEP 2: Set ITEM=STACK[TOP]
STEP 3: Set TOP=TOP-1
STEP 4: Return](https://image.slidesharecdn.com/datastructuredigvijay2ndyearii-sem2-140108063033-phpapp02/85/Data-structure-by-Digvijay-12-320.jpg)
![Program implementation of POP
operation
int pop()
{ int item;
if(TOP==-1)
{ printf(“n Stack is empty”);
getch();
exit(0);
}
else
{ item=stack[TOP];
TOP=TOP-1;
printf(“n Item deleted is= %d”, item);
}
return(item);
}](https://image.slidesharecdn.com/datastructuredigvijay2ndyearii-sem2-140108063033-phpapp02/85/Data-structure-by-Digvijay-13-320.jpg)
Data structure by Digvijay
- 1. STACK REPRESENTATION BY- DIGVIJAY SINGH KARAKOTI
- 2. WHAT IS STACK? Stack is the non-linear non-primitive data structure or an ordered pair of elements. A Stack is a LIFO structure which follows the principal of “LAST IN FIRST OUT”, which depicts the insertion of last element in the stack and deletion of first element from the stack from one end called “TOP” of the stack.
- 3. Some real life examples of Stack
- 4. APPLICATIONS OF STACK Expression evaluation Infix, Prefix and Postfix Notation Expression conversion Memory Management Recursion
- 5. OPERATIONS PERFORMED IN STACK The m or oper at i ons per f or m by aj ed st ack ar e: PU ( ) – Thi s oper at i on i s used SH t o i nser t t he el em ent i nt o t he st ack. So, i t i s al so know as n “I N TI O ” oper at i on. SER N PO ) - Thi s oper at i on i s used P( t o del et e or r et r i eve t he el em ent
- 6. PUSH OPERATION This function will add elements/items into the stack. Whenever we add an element into the stack the pointer TOP gets incremented as:TOP+1 or TOP++ This is used to show the position of the element in the stack.
- 7. PUSH operation on stack is to add values into the stack. Let us assume that 5 items 30, 20, 25, 10 and 40 are to be placed on the stack. The items can be inserted one by one as shown in following figure:-
- 8. ALGORITHM FOR PUSH OPERATIONITEM, TOP) PUSH(MAXSTK, STEP 1: If TOP = MAXSTK THEN [Stack already filled?] Print "OVERFLOW" Go to step 4 End if STEP 2: TOP = TOP + 1 [Increase TOP by 1] STEP 3: Set STK[TOP] = ITEM [Insert ITEM in new TOP position]
- 9. Program implementation of PUSH operation void push() { int item; If(TOP==maxsize-1) { printf(“n Stack is full”); getch(); exit(0); } else { printf(“n Enter the element to be inserted”); scanf(“%d”, &item); TOP=TOP+1; stack[TOP]=item; } }
- 10. POP OPERATION This function will delete elements/items from the stack. Whenever we add an element into the stack the pointer TOP gets decremented as:TOP-1 or TOP-This is used to show the position of the element in the stack
- 11. POP operation on stack is to delete or retrieve values from the stack. Let us assume that 4 items 15, 12, 10 and 5 are to be deleted from the stack. The items can be deleted one by one as shown in following figure:- Figure. Deletion operations
- 12. ALGORITHM FOR POP OPERATION POP[STACK,TOP,ITEM] STEP 1: If TOP=0 Print ”Underflow” STEP 2: Set ITEM=STACK[TOP] STEP 3: Set TOP=TOP-1 STEP 4: Return
- 13. Program implementation of POP operation int pop() { int item; if(TOP==-1) { printf(“n Stack is empty”); getch(); exit(0); } else { item=stack[TOP]; TOP=TOP-1; printf(“n Item deleted is= %d”, item); } return(item); }