#include<alloc.h>
struct list{
int
data;
struct
list *prev,*next;
}*head=NULL,*temp,*node;
void infirst(void), inpos(void),
inlast(void), delfront(void), delpos(void), dellast(void), display(void),
count(void);
int num,pos,empty(void);
char con;
int empty(void)
{
if(head==NULL)
{
clrscr();
printf("The
list is empty!!");
return
1;
}
return
0;
}
void main()
{
printf("\nMain
Menu\n1.Insert at first\n2.Insert at specified position\n3.Insert at
last\n4.Delete first\n5.Delete specified position\n6.Delete from
last\n7.Display\n8.Count number of nodes\n9.Exit\nEnter choice:");
scanf("%d",&num);
switch(num)
{
case
1:
infirst();
break;
case
2:
inpos();
break;
case
3:
inlast();
break;
case 4:
delfront();
break;
case
5:
delpos();
break;
case
6:
dellast();
break;
case
7:
display();
break;
case
8:
count();
break;
case
9:
clrscr();
exit();
default:
clrscr();
puts("\nWRONG
INPUT!!");
}
main();
}
void infirst(void)
{
do
{
printf("\nEnter
number:");
scanf("%d",&num);
temp=(struct
list*)malloc(sizeof(struct list));
temp->data=num;
temp->next=head;
temp->prev=NULL;
head=temp;
printf("\nContinue
[y/n]?:");
con=getche();
}while(con=='y'||con=='Y');
}
void inpos(void)
{
do
{
num=0;
temp=head;
printf("\nEnter
position to insert at:");
scanf("%d",&pos);
while(temp->next!=NULL)
{
num++;
if(num==pos-1)
break;
temp=temp->next;
}
printf("\nEnter
number:");
scanf("%d",&num);
node=(struct
list*)malloc(sizeof(struct list));
node->data=num;
node->next=temp->next;
node->prev=temp;
temp->next=node;
printf("\nContinue
[y/n]?:");
con=getche();
}
while(con=='y'||con=='Y');
}
void inlast(void)
{
do
{
printf("\nEnter
data:");
scanf("%d",&num);
temp=head;
while(temp->next!=NULL)
temp=temp->next;
node=(struct
list *)malloc(sizeof(struct list));
node->data=num;
node->next=NULL;
node->prev=temp;
temp->next=node;
printf("\nContinue
[y/n]?:");
con=getche();
}
while(con=='y'||con=='Y');
}
void delfront(void)
{
do
{
if(empty()==1)
break;
else
{
temp=head;
head=temp->next;
head->prev=NULL;
free(temp);
printf("\nContinue
[y/n]?:");
con=getche();
}
}
while(con=='y'||con=='Y');
}
void delpos(void)
{
do
{
if(empty()==1)
break;
else
{
num=0;
temp=head;
printf("\nEnter
position:");
scanf("%d",&pos);
while(temp->next!=NULL)
{
num++;
if(num==pos-1)
break;
temp=temp->next;
}
node=temp->next->next;
free(temp->next);
temp->next=node;
node->prev=temp;
printf("\nContinue
[y/n]?:");
con=getche();
}
}
while(con=='y'||con=='Y');
}
void dellast(void)
{
do
{
if(empty()==1)
break;
else
{
temp=head;
while(temp->next!=NULL)
{
node=temp;
temp=temp->next;
}
node->next=NULL;
free(temp);
printf("\nContinue
[y/n]?:");
con=getche();
}
}
while(con=='y'||con=='Y');
}
void display(void)
{
if(empty()==1)
return;
else
{
puts("The
list is:");
for(temp=head;temp!=NULL;temp=temp->next)
printf("%d
",temp->data);
}
}
void count(void)
{
num=0;
temp=head;
while(temp!=NULL)
{
num++;
temp=temp->next;
}
clrscr();
printf("\nTotal
number of nodes=%d",num);
}
