a double linked list hold a ptr to the previous node as well as the next one... below is a double linked list prog...
Code:
# include <iostream.h>
# include <conio.h>
# include <process.h>
class linked{
private:
int count;
struct node {
int val;
struct node *next;
struct node *prev;
};
struct node *head;
struct node *tail;
struct node *tailprev;
public:
linked();
createnode(int);
deletenode(int);
insertnode(int);
modify(int);
view(int);
search(int);
viewall();
browse();
int getnum();
};
linked::search(int sear)
{
if(count==0)
cout<<"\nThe linked list is empty..";
else
{
cout<<"\nThe nodes with that value are > \n\n\n";
node *present=head;
for(int i=0;i<count;i++)
{if(present->val==sear)
{
if(i<9)
cout<<"\nNode 00"<<i+1<<") "<<present->val<<" @ "<<present;
else
if(i>=9 && i<100)
cout<<"\nNode 0"<<i+1<<") "<<present->val<<" @ "<<present;
else
cout<<"\nNode "<<i+1<<") "<<present->val<<" @ "<<present;
}
present=present->next;
}
}
getch();
return 0;
}
linked::insertnode(int nodeadd)
{
if(nodeadd>count || nodeadd<1)
cout<<"Sorry the node number does not exist";
else
{
node* newnode=new node;
int nodeval;
cout<<"\nEnter the value for the inserted node > ";
cin>>nodeval;
newnode->val=nodeval;
node *present=head;
for(int i=1;i<nodeadd;i++)
{
present=present->next;
}
if(nodeadd!=1)
{
present->prev->next=newnode;
newnode->prev=present->prev;
newnode->next=present;
newnode->val=nodeval;
present->prev=newnode;
}
else
{
newnode->prev=present->prev;
newnode->next=present;
newnode->val=nodeval;
present->prev=newnode;
head=newnode;
}
count++;
cout<<"\nNode sucessfully inserted";
}
getch();
return 0;
}
linked::browse()
{
node *present=head;
char ch;
int co=1;
if(count==0)
cout<<"\nSorry no nodes present";
while(count!=0)
{
gotoxy(30,20);
cout<<" ";
gotoxy(30,20);
cout<<"Node "<<co<<") "<<present->val<<" @ address "<<present;
ch=getch();
if(ch==0x4d)
{
if(present->next!=NULL)
{
present=present->next;
co++;
}
}
if(ch==0x4b)
{
if(present->prev!=NULL)
{
present=present->prev;
co--;
}
}
if(ch==27)
break;
}
getch();
return 0;
}
linked::modify(int nodeno)
{
node *present=head;
if(nodeno>count || nodeno<1)
cout<<"\nThe node no "<<nodeno<<" does not exist.";
else
{
for(int i=1;i<nodeno;i++)
{
present=present->next;
}
cout<<"\nThe node "<<nodeno<<" contains the value "<<present->val<<" @ "<<present;
int newval;
cout<<"\nEnter the new value for the node > ";
cin>>newval;
present->val=newval;
cout<<"\nNode sucessfully modified.";
}
getch();
return 0;
}
linked::view(int nodeno)
{
node *present=head;
if(nodeno>count || nodeno<1)
cout<<"\nThe node no does not exist.";
else
{
for(int i=1;i<nodeno;i++)
{
present=present->next;
}
cout<<"\nThe node "<<nodeno<<" contains the value "<<present->val<<" @ "<<present;
}
getch();
return 0;
}
int linked::getnum()
{
return count;
}
linked::deletenode(int nodeno)
{
node *present=head;
if(nodeno>count || nodeno<1)
cout<<"\nThe node no does not exist.";
else
{
for(int i=1;i<nodeno;i++)
{
present=present->next;
}
node *temp=present;
if(temp->prev!=NULL && (nodeno!=count)&& nodeno!=1)
present->prev->next=present->next;
if(temp->next!=NULL &&(nodeno!=1))
present->next->prev=present->prev;
if(temp->prev==NULL)
{
present->next->prev=NULL;
head=present->next;
}
if(temp->next==NULL)
{
present->next=NULL;
tail=present;
}
cout<<"\n The Node no "<<nodeno<<" with value "<<present->val<<" sucessfully deleted";
count--;
}
getch();
return 0;
}
linked::viewall()
{
if(count==0)
cout<<"\nThe linked list is empty..";
else
{
cout<<"\nThe nodes are > \n\n\n";
node *present=head;
for(int i=0;i<count;i++)
{
if(i<9)
cout<<"\nNode 00"<<i+1<<") "<<present->val<<" @ "<<present;
else
if(i>=9 && i<100)
cout<<"\nNode 0"<<i+1<<") "<<present->val<<" @ "<<present;
else
cout<<"\nNode "<<i+1<<") "<<present->val<<" @ "<<present;
present=present->next;
}
}
return 0;
}
linked::linked()
{
count=0;
head=new node();
head->val=0;
head->next=NULL;
head->prev=NULL;
tail=head;
tailprev=tail;
}
linked::createnode(int newnod)
{
if(count==0)
{
head->val=newnod;
}
else
{
tail=new node;
tail->val=newnod;
tailprev->next=tail;
tail->next=NULL;
tail->prev=tailprev;
tailprev=tail;
}
count++;
return 0;
}
main()
{
int nodeno=0;
linked l1;
clrscr();
int option=0;
while(option!=10)
{
clrscr();
cout<<"\n M E N U";
cout<<"\n * * * *";
cout<<"\n\n\n No of nodes present > "<<l1.getnum();
cout<<"\n\n\n\n\n 1) Create a node";
cout<<"\n\n 2) Delete a node";
cout<<"\n\n 3) View All node";
cout<<"\n\n 4) View Particular node";
cout<<"\n\n 5) Modify a node";
cout<<"\n\n 6) Browse through node";
cout<<"\n\n 7) Insert node";
cout<<"\n\n 8) Search node";
cout<<"\n\n 9) Use loop to create nodes";
cout<<"\n\n 10) Exit";
cout<<"\n\n\n\n\n Option > ";
cin>>option;
clrscr();
if(option==1)
{
cout<<"\nEnter the value for node "<<l1.getnum()+1<<" > ";
cin>>nodeno;
l1.createnode(nodeno);
}
if(option==2)
{
cout<<"\nEnter the node no to be deleted > ";
cin>>nodeno;
l1.deletenode(nodeno);
}
if(option==3)
{
l1.viewall();
getch();
}
if(option==4)
{
cout<<"\nEnter the node no you want to view > ";
cin>>nodeno;
l1.view(nodeno);
}
if(option==5)
{
int newval;
cout<<"\nEnter the node no you want to modify > ";
cin>>nodeno;
l1.modify(nodeno);
}
if(option==6)
{
cout<<"\nTo browse use the left and right arrow keys...press esc to exit";
l1.browse();
}
if(option==7)
{
cout<<"\nEnter the position to insert node > ";
int node1;
cin>>node1;
l1.insertnode(node1);
}
if(option==8)
{
int searc;
cout<<"\nEnter the value you want to search > ";
cin>>searc;
l1.search(searc);
}
if(option==9)
{
int a,b,c;
cout<<"\nEnter the start point of loop > ";
cin>>a;
cout<<"Enter the limit for the loop > ";
cin>>b;
cout<<"Enter the step value > ";
cin>>c;
int cou=0;
for(int i=a;i<b;i=i+c)
{
cou++;
l1.createnode(i);
cout<<"\ncreating new node with value > "<<i;
}
cout<<"\n A total of "<<cou<<" nodes have been created";
getch();
}
}
return 0;
}
