Data Structure Programs

//PROGRAM FOR SINGLE LINKED LIST//

#include<stdio.h>

#include<conio.h>

struct node

{

 int data;

 struct node*next;

}*temp,*start,*prev,*ptr,*size;

void create();

void insert();

void finsert();

void minsert();

void einsert();

void delet();

void fdelet();

void mdelet();

void edelet();

void display();

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tSINGLE LINKED LIST");

 printf("\n\t\t\t------------------------------");

 while(1)

 {

  printf("\n\nMAIN MENU");

  printf("\n---------\n");

  printf("1.Create\n");

  printf("2.Insert\n");

  printf("3.Delete\n");

  printf("4.Display\n");

  printf("5.Exit\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:create();break;

   case 2:insert();break;

   case 3:delet();break;

   case 4:display();break;

   case 5:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

}

void create()

{

 int a;

 temp=(struct node*)malloc(sizeof(struct node));

 printf("\nEnter a new node:");

 scanf("%d",&a);

 temp->data=a;

 temp->next=NULL;

 if(start==NULL)

  start=temp;

 else

 {

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  ptr->next=temp;

 }

}

void insert()

{

 int choice1;

 while(1)

 {

  printf("\n\nINSERTION OPERTION");

  printf("\n------------------------------\n");

  printf("1.Front insertion\n");

  printf("2.MIDDLE insertion\n");

  printf("3.End insertion\n");

  printf("4.Back to main menu\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice1);

  switch(choice1)

  {

   case 1:finsert();break;

   case 2:minsert();break;

   case 3:einsert();break;

   case 4:return;

  }

 }

}

void finsert()

{

 int b;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&b);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=b;

 temp->next=start;

 start=temp;

 printf("\nA NODE IS INSERTED IN FRONT\n");

}

void minsert()

{

 int b,c;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&b);

 printf("\nEnter item after which it has to be inserted:");

 scanf("%d",&c);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=b;

 temp->next=NULL;

 for(ptr=start;ptr->data!=c;ptr=ptr->next);

 temp->next=ptr->next;

 ptr->next=temp;

 printf("\nA NODE IS INSERTED IN MIDDLE\n");

}

void einsert()

{

 int d;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&d);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=d;

 temp->next=NULL;

 for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

 ptr->next=temp;

 printf("\nA NODE IS INSERTED IN END\n");

}

void delet()

{

 int choice2;

 while(1)

 {

  printf("\n\nDELETION OPERTION");

  printf("\n------------------------------\n");

  printf("1.Front deletion\n");

  printf("2.Middle deletion\n");

  printf("3.End deletion\n");

  printf("4.Back to main menu\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice2);

  switch(choice2)

  {

   case 1:fdelet();break;

   case 2:mdelet();break;

   case 3:edelet();break;

   case 4:return;

  }

 }

}

void fdelet()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  ptr=start;

  start=ptr->next;

  printf("\nFRONT NODE IS DELETED\n");

 }

}

void mdelet()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  int e;

  printf("\nEnter the node to be deleted:");

  scanf("%d",&e);

  for(ptr=start;ptr->data!=e;ptr=ptr->next);

  for(prev=start;prev->next!=ptr;prev=prev->next);

  prev->next=ptr->next;

  printf("\nMIDDLE NODE IS DELETED\n");

 }

}

void edelet()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  for(prev=start;prev->next!=ptr;prev=prev->next);

  prev->next=NULL;

  printf("\nEND NODE IS DELETED\n");

 }

}

void display()

{

 printf("\nThe element in the list:");

 ptr=start;

 while(ptr->next!=NULL)

 {

  printf("%d->",ptr->data);

  ptr=ptr->next;

 }

 printf("%d->",ptr->data);

 printf("NULL");

}

SAMPLE OUTPUT:

                                     SINGLE LINKED LIST

                       

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:1

Enter a new node:5

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:2

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:1

Enter the node to be inserted:3

A NODE IS INSERTED IN FRONT

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:2

Enter the node to be inserted:1

Enter item after which it has to be inserted:3

A NODE IS INSERTED IN MIDDLE

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:3

Enter the node to be inserted:4

A NODE IS INSERTED IN END

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:4

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:4

The element in the list:3->1->5->4->NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:3

DELETION OPERTION

1.Front deletion

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:1

FRONT NODE IS DELETED

DELETION OPERTION

1.Front deletion       

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:2

Enter the node to be deleted:5

MIDDLE NODE IS DELETED

DELETION OPERTION

1.Front deletion

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:3

END NODE IS DELETED

DELETION OPERTION

1.Front deletion

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:4

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:4

The element in the list:1->NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:5

//PROGRAM FOR CIRCULAR  LINKED LIST//

#include<stdio.h>

#include<conio.h>

#include<malloc.h>

struct node

{

 int data;

 struct node*next;

}*start,*ptr,*temp,*prev;

void insert();

void delet();

void display();

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tCIRCULAR LINKED LIST");

 printf("\n\t\t\t------------------------------------");

 while(1)

 {

  printf("\n\nMENU");

  printf("\n----\n");

  printf("1.Insertion\n");

  printf("2.Deletion\n");

  printf("3.Display\n");

  printf("4.Exit\n");

  printf("\nEnter the choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:insert();break;

   case 2:delet();break;

   case 3:display();break;

   case 4:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

}

void insert()

{

 int a;

 temp=(struct node*)malloc(sizeof(struct node));

 printf("\nEnter a node to be inserted:");

 scanf("%d",&a);

 temp->data=a;

 temp->next=NULL;

 if(start==NULL)

  start=temp;

 else

 {

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  ptr->next=temp;

 }

}

void delet()

{

 int e;

 if(start==NULL)

  printf("\nCIRCULAR LINKED LIST IS EMPTY");

 else

 {

  printf("\nEnter the node to be deleted:");

  scanf("%d",&e);

  if(start->data==e)

  {

   ptr=start;

   start=ptr->next;

  }

  else

  {

   for(ptr=start;ptr->data!=e;ptr=ptr->next);

   for(prev=start;prev->next!=ptr;prev=prev->next);

   prev->next=ptr->next;

  }

 }

 printf("\nThe node %d is deleted",e);

}

void display()

{

 if(start==NULL)

  printf("\nCIRCULAR LINKED LIST IS EMPTY");

 else

 {

  printf("\nItems in the circular linked list:");

  ptr=start;

  while(ptr->next!=NULL)

  {

   printf("%d->",ptr->data);

   ptr=ptr->next;

  }

  printf("%d->",ptr->data);

  printf("%d",start->data);

 }

}

SAMPLE OUTPUT:

                                    CIRCULAR LINKED LIST

                

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:1

Enter a node to be insertd:3

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:1

Enter a node to be insertd:4

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:1

Enter a node to be insertd:5

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:3

Items in the circular linked list:3->4->5->3

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:2

Enter the node to be deleted:4

The node 4 is deleted

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:3

Items in the circular linked list:3->5->3

MENU

1.Insertion

2.Deletion

3.Display

4.Exit

Enter the choice:4

//PROGRAM FOR CIRCULAR QUEUE//

#include<stdio.h>

#include<conio.h>

void enqueue();

void dequeue();

void display();

int cqueue[100],front=-1,rear=0,size;

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tCIRCULAR QUEUE");

 printf("\n\t\t\t----------------------------");

 printf("\n\nEnter the size of the circular queue:");

 scanf("%d",&size);

 while(1)

 {

  printf("\n\nMENU");

  printf("\n----\n");

  printf("1.Enqueue\n");

  printf("2.Dequeue\n");

  printf("3.Display\n");

  printf("4.Exit\n");

  printf("\nEnter the choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:enqueue();break;

   case 2:dequeue();break;

   case 3:display();break;

   case 4:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

}

void enqueue()

{

 int x;

 if(front==(rear+1)%size)

  printf("\nCIRCULAR QUEUE IS FULL\n");

 else

 {

  printf("\nEnter the element to be inserted:");

  scanf ("%d",&x);

  if(front== -1)

   front=rear=0;

  else

   rear=(rear+1)%size;

  cqueue[rear]=x;

 }

}

void dequeue()

{

 if(front== -1)

  printf("\nCIRCULAR QUEUE IS EMPTY\n");

 else

 {

  printf("\nThe deleted number is %d",cqueue[front]);

  if(front==rear)

   front=rear= -1;

  else

   front=(front+1)%size;

 }

}

void display()

{

 int i=front;

 if(i== -1)

  printf("\nCIRCULAR QUEUE IS EMPTY");

 else

 {

  printf("\nItems in the circular queue:");

  while(i!=rear)

  {

   printf ("\t%d",cqueue[i]);

   i=(i+1)%size;

  }

  printf ("\t%d",cqueue[i]);

 }

}

SAMPLE OUTPUT:

                                      CIRCULAR QUEUE

                       

Enter the size of the circular queue:3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:6

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:9

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

CIRCULAR QUEUE IS FULL

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

Items in the circular queue:    3       6       9

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:2

The deleted number is 3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

Items in the circular queue:    6       9

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:4

//PROGRAM FOR QUEUE USING ARRAYS//

#include<stdio.h>

#include<conio.h>

void enqueue();

void dequeue();

void display();

int queue[100],front=0,rear=0,size;

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tQUEUE USING ARRAYS");

 printf("\n\t\t\t----------------------------------");

 printf("\n\nEnter the size of the queue:");

 scanf("%d",&size);

 while(1)

 {

  printf("\n\nMENU");

  printf("\n----\n");

  printf("1.Enqueue\n");

  printf("2.Dequeue\n");

  printf("3.Display\n");

  printf("4.Exit\n");

  printf("\nEnter the choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:enqueue();break;

   case 2:dequeue();break;

   case 3:display();break;

   case 4:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

 getch();

}

void enqueue()

{

 int x;

 if(rear==size)

  printf("\nQUEUE IS FULL\n");

 else

 {

  printf("\nEnter the element to be inserted:");

  scanf ("%d",&x);

  rear++;

  queue[rear]=x;

 }

}

void dequeue()

{

 if(rear==front)

  printf("\nQUEUE IS EMPTY\n");

 else

 {

  front++;

  printf("\nThe deleted number is %d",queue[front]);

  queue[front]=0;

 }

}

void display()

{

 int i;

 if(rear==front)

  printf("\nQUEUE IS EMPTY");

 else

 {

  printf("\nItems in the queue:");

  for (i=front+1;i<=rear;i++)

   printf ("\t%d",queue[i]);

 }

}

SAMPLE  OUTPUT:

                                     QUEUE USING ARRAYS

                       

Enter the size of the queue:3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:2

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:4

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:5

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

QUEUE IS FULL

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

Items in the queue:     2       4       5

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:2

The deleted number is 2

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

Items in the queue:     4       5

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:4

                        

//PROGRAM FOR QUEUE USING LINKED LIST//

#include<stdio.h>

#include<conio.h>

#include<alloc.h>

struct queue

{

 int data;

 struct queue *next;

}*front=NULL,*rear=NULL;

void enqueue();

void dequeue();

void display();

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tQUEUE USING LINKED LIST");

 printf("\n\t\t\t-----------------------------------------");

 while(1)

 {

  printf("\n\nMENU");

  printf("\n----\n");

  printf("1.Enqueue\n");

  printf("2.Dequeue\n");

  printf("3.Display\n");

  printf("4.Exit\n");

  printf("\nEnter the choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:enqueue();break;

   case 2:dequeue();break;

   case 3:display();break;

   case 4:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

}

void enqueue()

{

 struct queue *t;

 int number;

 printf ("\nEnter the data:");

 scanf ("%d",&number);

 t=(struct queue *)malloc(sizeof(struct queue));

 t->data=number;

 t->next=NULL;

 if(rear==NULL)

 {

  rear=t;

  front=t;

 }

 else

 {

  rear->next=t;

  rear=t;

 }

}

void dequeue()

{

 int x;

 if(front==NULL)

  printf ("\nQUEUE UNDERFLOW");

 else

 {

  x=front->data;

  front=front->next;

  printf("\nThe deleted number is %d",x);

 }

}

void display()

{

 struct queue *q=front;

 if(front==NULL)

  printf ("\nQUEUE UNDERFLOW");

 else

 {

  printf("\nItems in the queue:");

  while(q!=NULL)

  {

   printf("%d->",q->data);

   q=q->next;

  }

  printf("NULL");

 }

}

SAMPLE  OUTPUT:

                                     QUEUE USING LINKED LIST

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the data:3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the data:5

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the data:7

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

Items in the queue:3->5->7->NULL

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:2

The deleted number is 3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

Items in the queue:5->7->NULL

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:4

//PROGRAM FOR DOUBLE ENDED QUEUE //

#include<stdio.h>

#include<conio.h>

struct node

{

 int data;

 struct node*next;

}*temp,*start,*prev,*ptr,*size;

void create();

void insert();

void finsert();

void einsert();

void delet();

void fdelet();

void edelet();

void display();

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tDOUBLE ENDED QUEUE");

 printf("\n\t\t\t-----------------------------------");

 while(1)

 {

  printf("\n\nMAIN MENU");

  printf("\n---------------\n");

  printf("1.Create\n");

  printf("2.Insert\n");

  printf("3.Delete\n");

  printf("4.Display\n");

  printf("5.Exit\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:create();break;

   case 2:insert();break;

   case 3:delet();break;

   case 4:display();break;

   case 5:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

}

void create()

{

 int item;

 temp=(struct node*)malloc(sizeof(struct node));

 printf("\nEnter a new node value:");

 scanf("%d",&item);

 temp->data=item;

 temp->next=NULL;

 if(start==NULL)

  start=temp;

 else

 {

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  ptr->next=temp;

 }

}

void insert()

{

 int choice1;

 while(1)

 {

  printf("\n\nINSERTION OPERTION");

  printf("\n------------------\n");

  printf("1.Front insertion\n");

  printf("2.End insertion\n");

  printf("3.Back to main menu\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice1);

  switch(choice1)

  {

   case 1:finsert();break;

   case 2:einsert();break;

   case 3:return;

  }

 }

}

void finsert()

{

 int b;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&b);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=b;

 temp->next=start;

 start=temp;

 printf("\nA NODE IS INSERTED IN FRONT\n");

}

void einsert()

{

 int c;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&c);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=c;

 temp->next=NULL;

 for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

 ptr->next=temp;

 printf("\nA NODE IS INSERTED IN END\n");

}

void delet()

{

 int choice2;

 while(1)

 {

  printf("\n\nDELETION OPERTION");

  printf("\n-----------------\n");

  printf("1.Front deletion\n");

  printf("2.End deletion\n");

  printf("3.Back to main menu\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice2);

  switch(choice2)

  {

   case 1:fdelet();break;

   case 2:edelet();break;

   case 3:return;

  }

 }

}

void fdelet()

{

 ptr=start;

 start=ptr->next;

 printf("\nFRONT NODE IS DELETED\n");

}

void edelet()

{

 for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

 for(prev=start;prev->next!=ptr;prev=prev->next);

 prev->next=NULL;

 printf("\nEND NODE IS DELETED\n");

}

void display()

{

 printf("\nThe element in the list:");

 ptr=start;

 while(ptr->next!=NULL)

 {

  printf("%d->",ptr->data);

  ptr=ptr->next;

 }

 printf("%d->",ptr->data);

 printf("NULL");

}

SAMPLE OUTPUT:

                                      DOUBLE ENDED QUEUE

                      

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:1

Enter a new node value:5

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:2

INSERTION OPERTION

1.Front insertion

2.End insertion

3.Back to main menu

Enter your choice:1

Enter the node to be inserted:6

A NODE IS INSERTED IN FRONT

INSERTION OPERTION

1.Front insertion

2.End insertion

3.Back to main menu

Enter your choice:2

Enter the node to be inserted:3

A NODE IS INSERTED IN END

INSERTION OPERTION

1.Front insertion

2.End insertion

3.Back to main menu

Enter your choice:3

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:4

The element in the list:6->5->3->NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:3

DELETION OPERTION

1.Front deletion

2.End deletion

3.Back to main menu

Enter your choice:1

FRONT NODE IS DELETED

DELETION OPERTION

1.Front deletion

2.End deletion

3.Back to main menu

Enter your choice:3

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:4

The element in the list:5->3->NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:3

DELETION OPERTION

1.Front deletion

2.End deletion

3.Back to main menu

Enter your choice:2

END NODE IS DELETED

DELETION OPERTION

1.Front deletion

2.End deletion

3.Back to main menu

Enter your choice:3

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:4

The element in the list:5->NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Display

5.Exit

Enter your choice:5

//PROGRAM FOR PRIORITY QUEUE//

#include<stdio.h>

#include<conio.h>

void enqueue();

void dequeue();

void display();

void priority();

int queue[100],front=0,rear=0,size;

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tPRIORITY QUEUE");

 printf("\n\t\t\t--------------------------");

 printf("\n\nEnter the size of the queue:");

 scanf("%d",&size);

 while(1)

 {

  printf("\n\nMENU");

  printf("\n----\n");

  printf("1.Enqueue\n");

  printf("2.Dequeue\n");

  printf("3.Display\n");

  printf("4.Exit\n");

  printf("\nEnter the choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:enqueue();break;

   case 2:dequeue();break;

   case 3:display();break;

   case 4:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

 getch();

}

void enqueue()

{

 int x;

 if(rear==size)

  printf("\nQUEUE IS FULL\n");

 else

 {

  printf("\nEnter the element to be inserted:");

  scanf ("%d",&x);

  rear++;

  queue[rear]=x;

  priority();

 }

}

void dequeue()

{

 if(rear==front)

  printf("\nQUEUE IS EMPTY\n");

 else

 {

  front++;

  printf("\nThe deleted number is %d",queue[front]);

  queue[front]=0;

 }

}

void display()

{

 int i;

 if(rear==front)

  printf("\nQUEUE IS EMPTY");

 else

 {

  printf("\nThe priority queue:");

  for (i=front+1;i<=rear;i++)

   printf ("\t%d",queue[i]);

 }

}

void priority()

{

 int i,j,temp;

 for(i=front;i<=rear-1;i++)

 {

  for(j=front;j<rear;j++)

  {

   if(queue[j]>queue[j+1])

   {

    temp=queue[j];

    queue[j]=queue[j+1];

    queue[j+1]=temp;

   }

  }

 }

}

SAMPLE OUTPUT:

                                      PRIORITY QUEUE

Enter the size of the queue:3

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:4

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:6

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

Enter the element to be inserted:2

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:1

QUEUE IS FULL

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:3

The priority queue:     2       4       6

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:2

The deleted number is 2

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice: 3

The priority queue:     4       6

MENU

1.Enqueue

2.Dequeue

3.Display

4.Exit

Enter the choice:4

//PROGRAM FOR DOUBLY LINKED LIST//

#include<stdio.h>

#include<conio.h>

struct node

{

 int data;

 struct node *next;

 struct node *prev;

}*start,*ptr,*temp;

void create();

void insert();

void finsert();

void minsert();

void einsert();

void delet();

void fdelet();

void mdelet();

void edelet();

void fdisplay();

void rdisplay();

void main()

{

 int choice;

 clrscr();

 printf("\n\t\t\tDOUBLY LINKED LIST");

 printf("\n\t\t\t---------------------------------");

 while(1)

 {

  printf("\n\nMAIN MENU");

  printf("\n----------\n");

  printf("1.Create\n");

  printf("2.Insert\n");

  printf("3.Delete\n");

  printf("4.Forward display\n");

  printf("5.Reverse display\n");

  printf("6.Exit\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice);

  switch(choice)

  {

   case 1:create();break;

   case 2:insert();break;

   case 3:delet();break;

   case 4:fdisplay();break;

   case 5:rdisplay();break;

   case 6:exit();break;

   default:printf("wrong choice");

               exit();

  }

 }

}

void create()

{

 int a;

 temp=(struct node*)malloc(sizeof(struct node));

 printf("\nEnter a new node:");

 scanf("%d",&a);

 temp->data=a;

 temp->next=NULL;

 temp->prev=NULL;

 if(start==NULL)

  start=temp;

 else

 {

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  ptr->next=temp;

  temp->prev=ptr;

 }

}

void insert()

{

 int choice1;

 while(1)

 {

  printf("\n\nINSERTION OPERTION");

  printf("\n---------------------------------\n");

  printf("1.Front insertion\n");

  printf("2.MIDDLE insertion\n");

  printf("3.End insertion\n");

  printf("4.Back to main menu\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice1);

  switch(choice1)

  {

   case 1:finsert();break;

   case 2:minsert();break;

   case 3:einsert();break;

   case 4:return;

  }

 }

}

void finsert()

{

 int b;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&b);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=b;

 temp->next=start;

 ptr->prev=temp;

 start=temp;

 printf("\nA NODE IS INSERTED IN FRONT\n");

}

void minsert()

{

 int b,c;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&b);

 printf("\nEnter item after which it has to be inserted:");

 scanf("%d",&c);

 temp=(struct node*)malloc(sizeof(struct node));

 temp->data=b;

 temp->next=NULL;

 for(ptr=start;ptr->data!=c;ptr=ptr->next);

 temp->prev=ptr;

 temp->next=ptr->next;

 ptr->next->prev=temp;

 ptr->next=temp;

 printf("\nA NODE IS INSERTED IN MIDDLE\n");

}

void einsert()

{

 int d;

 printf("\nEnter the node to be inserted:");

 scanf("%d",&d);

 temp=(struct node*)malloc(sizeof(struct node));

 for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

 temp->data=d;

 temp->next=NULL;

 temp->prev=ptr;

 ptr->next=temp;

 printf("\nA NODE IS INSERTED IN END\n");

}

void delet()

{

 int choice2;

 while(1)

 {

  printf("\n\nDELETION OPERTION");

  printf("\n--------------------------------\n");

  printf("1.Front deletion\n");

  printf("2.Middle deletion\n");

  printf("3.End deletion\n");

  printf("4.Back to main menu\n");

  printf("\nEnter your choice:");

  scanf("%d",&choice2);

  switch(choice2)

  {

   case 1:fdelet();break;

   case 2:mdelet();break;

   case 3:edelet();break;

   case 4:return;

  }

 }

}

void fdelet()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  ptr=start;

  start=ptr->next;

  printf("\nFRONT NODE IS DELETED\n");

 }

}

void mdelet()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  int e;

  printf("\nEnter the node to be deleted:");

  scanf("%d",&e);

  for(ptr=start;ptr->data!=e;ptr=ptr->next);

  ptr->next->prev=ptr->prev;

  ptr->prev->next=ptr->next;

  printf("\nMIDDLE NODE IS DELETED\n");

 }

}

void edelet()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  ptr->prev->next=NULL;

  printf("\nEND NODE IS DELETED\n");

 }

}

void fdisplay()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY\n");

 else

 {

  printf("\nDISPLAY IN FORWARD ORDER:");

  printf("NULL");

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next)

  {

   printf("<=>%d",ptr->data);

  }

  printf("<=>%d<=>",ptr->data);

  printf("NULL");

 }

}

void rdisplay()

{

 if(start==NULL)

  printf("\nTHE LIST IS EMPTY");

 else

 {

  printf("\nDISPLAY IN REVERSE ORDER:");

  printf("NULL");

  for(ptr=start;ptr->next!=NULL;ptr=ptr->next);

  while(ptr!=start)

  {

   printf("<=>%d",ptr->data);

   ptr=ptr->prev;

  }

  printf("<=>%d<=>",ptr->data);

  printf("NULL");

 }

}

SAMPLE OUTPUT:

                                    DOUBLY LINKED LIST

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:1

Enter a new node:3

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:2

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:1

Enter the node to be inserted:4

A NODE IS INSERTED IN FRONT

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:2

Enter the node to be inserted:5

Enter item after which it has to be inserted:4

A NODE IS INSERTED IN MIDDLE

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:3

Enter the node to be inserted:7

A NODE IS INSERTED IN END

INSERTION OPERTION

1.Front insertion

2.MIDDLE insertion

3.End insertion

4.Back to main menu

Enter your choice:4

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:4

DISPLAY IN FORWARD ORDER:NULL<=>4<=>5<=>3<=>7<=>NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:5

DISPLAY IN REVERSE ORDER:NULL<=>7<=>3<=>5<=>4<=>NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:3

DELETION OPERTION

1.Front deletion

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:1

FRONT NODE IS DELETED

DELETION OPERTION

1.Front deletion

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:3

END NODE IS DELETED

DELETION OPERTION

1.Front deletion

2.Middle deletion

3.End deletion

4.Back to main menu

Enter your choice:4

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice: 4

DISPLAY IN FORWARD ORDER:NULL<=>1<=>3<=>NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:5

DISPLAY IS REVERSE ORDER:NULL<=>3<=>1<=>NULL

MAIN MENU

1.Create

2.Insert

3.Delete

4.Forward display

5.Reverse display

6.Exit

Enter your choice:6

//PROGRAM FOR INFIX TO POSTFIX//

#include<stdio.h>

#include<conio.h>

#include<alloc.h>

char inf[40],post[40];

int top=0,st[20];

void postfix();

void push(int);

char pop();

void main()

{

 clrscr();

 printf ("\n\t\tINFIX TO POSTFIX");

 printf ("\n\t\t---------------------------");

 printf("\n\nEnter the infix expression:");

 scanf("%s",inf);

 postfix();

 getch();

}

void postfix()

{

 int i,j=0;

 for(i=0;inf[i]!='\0';i++)

 {

  switch(inf[i])

  {

   case '+': while(st[top]>=1)

                  post[j++]=pop();

                 push(1);

                 break;

   case '-': while(st[top]>=1)

                  post[j++]=pop();

                 push(2);

                 break;

   case '*':while(st[top]>=3)

                  post[j++]=pop();

                 push(3);

                 break;

   case '/': while(st[top]>=3)

                  post[j++]=pop();

                 push(4);

                 break;

   case '^': while(st[top]>=4)

                  post[j++]=pop();

                 push(5);

                 break;

   case '(': push(0);

                 break;

   case ')': while(st[top]!=0)

                  post[j++]=pop();

                 top--;

                 break;

   default:post[j++]=inf[i];

  }

 }

 while(top>0)

 post[j++]=pop();

 printf("\nThe postfix expression is %s",post);

}

void push(int ele)

{

 top++;

 st[top]=ele;

}

char pop()

{

 int e1;

 char e;

 e1=st[top];

 top--;

 switch(e1)

 {

  case 1:e='+';

             break;

  case 2:e='-';

             break;

  case 3:e='*';

             break;

  case 4:e='/';

             break;

  case 5:e='^';

             break;

 }

 return (e);

}

SAMPLE OUTPUT:

                                     INFIX TO POSTFIX

Enter the infix expression: a+b*c/d-e

The postfix expression is abc*d/+e-