#include<stdio.h>
#include<stdlib.h>
typedef struct circular
{
int val;
struct circular *next;
}cir;
void enqueue(cir **,int);
int dequeue(cir **);
int isempty(cir *);
int peek(cir *);
void disp(cir *);
void main()
{
cir *h=NULL;
int v,p;
while(1)
{
printf("\n1. Insert value \n2. Delete value \n3. Display Front value \n4. Display Queue elements \n5. Exit");
printf("\n\n Enter the choice : ");
scanf("%d",&p);
switch(p)
{
case 1:printf("\n Enter the value : ");
scanf("%d",&v);
enqueue(&h,v);
break;
case 2: v=dequeue(&h);
printf("\n\n Deleted value is : %d",v);
break;
case 3:
v=peek(h);
printf("\n\n Front value is : %d",v);
break;
case 4:printf("\n\n The elements in the queue are : ");
disp(h);
break;
case 5: exit(0);
default:printf("\n\n Not a proper choice");
}
}
}
void enqueue(cir **h,int v)
{
cir *ptr,*temp;
temp=(cir *)malloc(sizeof(cir));
temp->val=v;
temp->next=NULL;
if(*h==NULL)
{
*h=temp;
}
else
{
ptr=*h;
while(ptr->next!=*h)
ptr=ptr->next;
ptr->next=temp;
}
temp->next=*h;
}
int dequeue(cir **h)
{
int p;
cir *temp;
temp=*h;
while(temp->next!=*h)
temp=temp->next;
p=(*h)->val;
*h=(*h)->next;
temp->next=*h;
return p;
}
int isempty(cir *h)
{
if(h==NULL)
return 1;
else
return 0;
}
int peek(cir *h)
{
return h->val;
}
void disp(cir *h)
{
cir *ptr;
ptr=h;
while(ptr->next!=h)
{
printf("|%2d|",ptr->val);
ptr=ptr->next;
}
printf("%2d|",ptr->val);
}
