/* Program to implement dequeue using linked list */
#include
#include
#define new1 (nd *)malloc(sizeof(nd))
typedef struct deque
{
int info;
struct deque *next;
}nd;
void display(nd *ptr)
{
if(ptr==NULL)
printf("\nQueue is empty...\n");
else
{
printf("\nQueue : ");
while(ptr!=NULL)
{
printf(" %d --> ",ptr->info);
ptr=ptr->next;
}
printf("\b\b\b\b ");
printf("\n");
}
}
void insfront(nd **ptr)
{
if(*ptr==NULL)
{
*ptr=new1;
printf("\nEnter the element : ");
scanf("%d",&(*ptr)->info);
(*ptr)->next=NULL;
}
else
{
nd *t;
t=new1;
printf("\nEnter the element : ");
scanf("%d",&t->info);
t->next=*ptr;
*ptr=t;
}
}
void insrear(nd **ptr)
{
nd *c=*ptr;
if(*ptr==NULL)
{
*ptr=new1;
printf("\nEnter the element : ");
scanf("%d",&(*ptr)->info);
(*ptr)->next=NULL;
}
else
{
nd *t;
t=new1;
printf("\nEnter the element : ");
scanf("%d",&t->info);
while(c->next!=NULL)
c=c->next;
t->next=NULL;
c->next=t;
}
}
void delfront(nd **ptr)
{
nd *c=*ptr,*t=*ptr;
if(*ptr==NULL)
printf("\nQueue is empty...");
else if(t->next==NULL) // If queue contains single node
{
*ptr=NULL;
free(t);
}
else
{
*ptr=c->next;
free(c);
}
}
void delend(nd **ptr)
{
nd *c=*ptr,*t=*ptr,*p;
if(*ptr==NULL)
printf("\nQueue is empty...");
else if(t->next==NULL) // If queue contains single node
{
*ptr=NULL;
free(t);
}
else
{
while(c->next!=NULL)
{
p=c;
c=c->next;
}
p->next=NULL;
free(c);
}
}
main()
{
int n;
nd *h;
h=NULL;
printf("\nProgram to implement dequeue using linked list :\n");
int ch1,ch2,ch3,ch4,ch5,ch6,ch7;
do
{
printf("\n[1] Create input restricted queue \n[2] Create output restricted queue ");
printf("\n[3] Quit from program \n");
printf("\nEnter your choice : ");
scanf("%d",&ch1);
switch(ch1)
{
case 1:
do
{
printf("\n[1] Insert at front restricted \n[2] Insert at end restricted ");
printf("\n[3] Quit to previous menu \n");
printf("\nEnter your choice : ");
scanf("%d",&ch2);
switch(ch2)
{
case 1:
do
{
printf("\n[1] Insert at end [2] Delete from front ");
printf("\n[3] Delete from end [4] Quit to previous menu \n");
printf("\nEnter your choice : ");
scanf("%d",&ch3);
switch(ch3)
{
case 1:
insrear(&h);
display(h);
break;
case 2:
delfront(&h);
display(h);
break;
case 3:
delend(&h);
display(h);
break;
case 4:
break;
default:printf("\nEnter correct choice..\n");
break;
}
}while(ch3!=4);
break;
case 2:
do
{
printf("\n[1] Insert at front [2] Delete from front ");
printf("\n[3] Delete from end [4] Quit to previous menu \n");
printf("\nEnter your choice : ");
scanf("%d",&ch4);
switch(ch4)
{
case 1:
insfront(&h);
display(h);
break;
case 2:
delfront(&h);
display(h);
break;
case 3:
delend(&h);
display(h);
case 4:
break;
default:printf("\nEnter correct choice...\n");
break;
}
}while(ch4!=4);
break;
case 3:
break;
default:printf("\nEnter correct choice...\n");
break;
}
}while(ch2!=3);
break;
case 2:
do
{
printf("\n[1] Delete at front restricted [2] Delete at end restricted ");
printf("\n[3] Quit to previous menu \n");
printf("\nEnter your choice : ");
scanf("%d",&ch5);
switch(ch5)
{
case 1:
do
{
printf("\n[1] Insert at front [2] Insert at end ");
printf("\n[3] Delete from end [4] Quit to previous menu \n");
printf("\nEnter your choice : ");
scanf("%d",&ch6);
switch(ch6)
{
case 1:
insfront(&h);
display(h);
break;
case 2:
insrear(&h);
display(h);
break;
case 3:
delend(&h);
display(h);
break;
case 4:
break;
default:printf("\nEnter correct choice...\n");
break;
}
}while(ch6!=4);
break;
case 2:
do
{
printf("\n[1] Insert at front [2] Insert at end ");
printf("\n[3] Delete from front [4] Quit to previous menu \n");
printf("\nEnter your choice : ");
scanf("%d",&ch7);
switch(ch7)
{
case 1:
insfront(&h);
display(h);
break;
case 2:
insrear(&h);
display(h);
break;
case 3:
delfront(&h);
display(h);
break;
case 4:
break;
default:printf("\nEnter correct choice...\n");
break;
}
}while(ch7!=4);
break;
case 3:
break;
default:printf("\nEnter correct choice...\n");
break;
}
}while(ch5!=3);
case 3:
break;
default:printf("\nEnter correct choice ... \n");
break;
}
}while(ch1!=3);
}
