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Showing posts with label Doubly Linked List. Show all posts
Showing posts with label Doubly Linked List. Show all posts
Wednesday, November 13, 2013
Design,Develop and execute a program in C to implement a doubly linked list where each node consists of integers.The program should support the following operations:
1.Create a doubly linked list by adding each node at the front.
2.Insert a new node to the left of the node whose key value is read as an input.
3.Delete the node of a given data if it’s found, otherwise display appropriate message
4.Display the contents of the list.
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
typedef struct node *NODE;
struct node
{
int info;
NODE left,right;
};
NODE first;
int empty();
void create();
void insert();
void delete();
void display();
NODE getnode()
{
return((struct node*)malloc(sizeof(struct node)));
}
int empty()
{
return(first==NULL?1:0);
}
void create()
{
NODE new;
int ch;
first=NULL;
do
{
new=getnode();
printf("\n enter element to be inserted:");
scanf("%d",&new->info);
new->left=new->right=NULL;
if(first==NULL)
{
first=new;
}
else
{
new->right=first;
first->left=new;
first=new;
}
printf("\n continue?1\0");
scanf("%d",&ch);
}
while(ch!=0);
}
void insert()
{
NODE new,curr,prev;
int x,f=0;
printf("\n enter the key value of a node\n");
scanf("%d",&x);
if(x==first->info)
{
new=getnode();
printf("\n enter a value for new node to be inserted:\n");
scanf("%d",&new->info);
new->left=new->right=NULL;
new->right=first;
first=new;
}
else
{
curr=first->right;
while(curr!=NULL)
{
if(x==curr->info)
{
f=1;
break;
}
curr=curr->right;
}
if(f)
{
new=getnode();
printf("\n enter a value to be inserted \n");
scanf("%d",&new->info);
new->left=new->right=NULL;
prev=curr->left;
new->right=curr;
curr->left=new;
prev->right=new;
new->left=prev;
}
else
{
printf("\n invalid key value \n");
}
}
}
void delete()
{
NODE curr,prev;
int f=0,x;
printf("\n enter info value of node you want to delete \n");
scanf("%d",&x);
if(x==first->info)
{
curr=first;
first=first->right;
first->left=NULL;
printf("\n deleted item %d",curr->info);
free(curr);
}
else
{
curr=first->right;
while(curr!=NULL)
{
if(x==curr->info)
{
f=1;
break;
}
curr=curr->right;
}
if(f)
{
prev=curr->left;
prev->right=curr->right;
curr->right->left=prev;
free(curr);
}
else
printf("\n not valid node!! not found \n");
}
}
void display()
{
NODE curr;
printf("\n elements of the list \n");
printf("\n NULL<-");
for(curr=first;curr!=NULL;curr=curr->right)
{
printf("%d<-->",curr->info);
}
printf("NULL \n");
}
void main()
{
int ch;
clrscr();
printf("\n \n doubly linked list will be created \n");
create();
display();
printf("\n\n doubly linked list will be created \n");
printf("\t1->insert\n");
printf("\t2->delete\n");
printf("\t3->display\n");
printf("\t4->exit\n");
while(1)
{
printf("enter your choice \n");
scanf("%d",&ch);
switch(ch)
{
case 1:
if(first==NULL)
{
printf("empty list \n");
printf("insert left not possible \n");
}
else
{
insert();
display();
}
break;
case 2:
if(empty())
printf("\n empty list \n");
else
{
delete();
if(!empty())
display();
}
break;
case 3:
if(empty())
printf("\n empty list \n");
else
{
display();
}
break;
case 4:
exit(0);
default:
printf("\n invalid choice!!");
}
}
getch();
}
Program end
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