DSA LAB PROGRAM. Write a program to illustrate the working of a Queue which is implemented using pointers. But note that the memory space occupied by a node in a linked representation is not exactly twice the space used by an element of array representation.

#include

#include

Struct node

{

int info;

struct node *link;

}*front,*rear,*newptr,*save;

main()

{

int ele,opt;

void insert(int);

int delete(struct node*);

void display(struct node*);

rear=NULL;

front=NULL;

while(1)

{

printf("\n Main menu ");

printf("\n\t1. Insert");

printf("\n\t2. Delete");

printf("\n\t3. Display");

printf("\n\t4. Exit");

printf("\n Enter ur choice");

scanf("%d",&opt);

switch(opt)

{

case 1:

printf("\n Enter element to insert");

scanf("%d",&ele);

insert(ele);

break;

case 2:

ele=delete(front);

printf("\n Deleted element=%d",ele);

break;

case 3:

display(queue);

break;

case 4:

exit(0);

break;

default :

printf("\n Wrong choice");

break;

}

}

}

void insert(int ele)

{

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

newptr->info=ele;

newptr->link=NULL;

if(rear==NULL)

{

rear=newptr;

front=newptr;

}

else

rear->link=newptr;

}

int delete(struct node *front)

{

int ele;

if(front==NULL)

{

printf("\n queue is empty");

return(0);

}

else

{

ele=front->info;

if(front==rear)

{

front=NULL;

rear=NULL;

}

else

front=front->link;

return(ele);

}

}

 void display(struct node *front)

{

save=front;

while(save!=NULL)

{

printf(“\t%d”,save->info);

save=save->link;

}

}

Output:

Main menu

1.      Insert

2.      Delete

3.      Display

4.      Exit

Enter ur choice1

Enter element to insert424

Main menu

1.      Insert

2.      Delete

3.      Display

4.      Exit

Enter ur choice3

424

Main menu

1.      Insert

2.      Delete

3.      Display

4.      Exit

Enter ur choice2

Deleted element=424

Main menu

1.      Insert

2.      Delete

3.      Display

4.      Exit

Enter ur choice4