C++ Programming Code Examples
C++ > Data Structures Code Examples
Single linked list
/* Single linked list */
#include<iostream.h>
#include<conio.h>
#include<stdlib.h>
class list
{
struct node
{
int data;
node *link;
}*p;
public:
void inslast(int);
void insbeg(int);
void insnext(int,int);
void delelement(int);
void delbeg();
void dellast();
void disp();
int seek(int);
list(){p=NULL;}
~list();
};
void list::inslast(int x)
{
node *q,*t;
if(p==NULL)
{
p=new node;
p->data=x;
p->link=NULL;
}
else
{
q=p;
while(q->link!=NULL)
q=q->link;
t=new node;
t->data=x;
t->link=NULL;
q->link=t;
}
cout<<"
Inserted successfully at the end..
";
disp();
}
void list:: insbeg(int x)
{
node *q;
q=p;
p=new node;
p->data=x;
p->link=q;
cout<<"
Inserted successfully at the begining..
";
disp();
}
void list::delelement(int x)
{
node *q,*r;
q=p;
if(q->data==x)
{
p=q->link;
delete q;
return;
}
r=q;
while(q!=NULL)
{
if(q->data==x)
{
r->link=q->link;
delete q;
return;
}
r=q;
q=q->link;
}
cout<<"
Element u entered "<<x<<" is not found..
";
}
void list:: delbeg()
{
cout<<"
The list before deletion:
";
disp();
node *q;
q=p;
if(q==NULL)
{
cout<<"
No data is present..
";
return;
}
p=q->link;
delete q;
return;
}
void list:: dellast()
{
cout<<"
The list before deletion:
";
disp();
node *q,*t;
q=p;
if(q==NULL)
{
cout<<"
There is no data in the list..
";
return;
}
if(q->link==NULL)
{
p=q->link;
delete q;
return;
}
while(q->link->link!=NULL)
q=q->link;
q->link=NULL;
return;
}
list::~list()
{
node *q;
if(p==NULL) return;
while(p!=NULL)
{
q=p->link;
delete p;
p=q;
}
}
void list::disp()
{
node *q;
q=p;
if(q==NULL)
{
cout<<"
No data is in the list..
";
return;
}
cout<<"
The items present in the list are :
";
while(q!=NULL)
{
cout<<" "<<q->data;
q=q->link;
}
}
void list :: insnext(int value,int position)
{
node *temp,*temp1;
temp=p;
if(temp1==NULL)
{
temp1= new node;
temp1->data=value;
temp1->link=NULL;
p=temp1;
return;
}
for(int i=0;((i<position)&&(temp->link!=NULL)) ;i++)
{
if(i==(position-1))
{
temp1= new node;
temp1->data= value;
temp1->link=temp->link;
temp->link=temp1;
}
temp=temp->link;
}
//cout<<"
Inserted successfully at the position.."<<position;
disp();
}
int list::seek(int value)
{
node *temp;
temp=p;
int position=0;
while(temp!=NULL)
{
if(temp->data==value)
return position+1;
else
{
temp=temp->link;
position=position+1;
}
}
cout<<"
Element "<<value<<" not found";
return 0;
}
void main()
{
list l;
int ch,v,p,ps;
do
{
clrscr();
cout<<"
Operations on List..
";
cout<<"
1.Insertion
2.Deletion
3.Display
4.Seek
5.Exit";
cout<<"
Enter ur choice:";
cin>>ch;
switch(ch)
{
case 1:
cout<<"
1.Insertion at begining
2.Insertion at the end
";
cout<<"3.Insertion after the mentioned position
";
cout<<"
Enter ur choice:";
cin>>ps;
cout<<"
Enter the value to insert:";
cin>>v;
switch(ps)
{
case 1:
l.insbeg(v);
break;
case 2:
l.inslast(v);
break;
case 3:
cout<<"
Enter the position to insert the value:";
cin>>p;
l.insnext(v,p);
break;
default:
cout<<"
The choice is invalid
";
return;
}
break;
case 2:
cout<<"
1.Delete the first element
2.Delete the last element";
cout<<"
3.Enter the element to delete from the list";
cout<<"
Enter ur choice:";
cin>>ps;
switch(ps)
{
case 1:
l.delbeg();
cout<<"
The list after deletion:
";l.disp();
break;
case 2:
l.dellast();
cout<<"
The list after deletion:
";l.disp();
break;
case 3:
l.disp();
cout<<"
Enter the element to delete : ";
cin>>v;
l.delelement(v);
cout<<"
The list after deletion:
";l.disp();
break;
default:
cout<<"
The option is invalid...
";
break;
}
break;
case 3:
l.disp();
break;
case 4:
l.disp();
cout<<"
Enter the element to search:";
cin>>v;
cout<<"
The position of the element "<< v<<" is "<<l.seek(v);
getch();
break;
case 5:
exit(1);
default:
cout<<"
The option is invalid...
";
return;
}
getch();
}while(ch!=5);
getch();
return;
}
The cin object is used to accept input from the standard input device i.e. keyboard. It is defined in the iostream header file. C++ cin statement is the instance of the class istream and is used to read input from the standard input device which is usually a keyboard. The extraction operator(>>) is used along with the object cin for reading inputs. The extraction operator extracts the data from the object cin which is entered using the keyboard. The "c" in cin refers to "character" and "in" means "input". Hence cin means "character input". The cin object is used along with the extraction operator >> in order to receive a stream of characters.
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