circular linked list in c++ pdf code example
Example: Circular Linked List in c++
#include <iostream>
using namespace std;
#define NULL 0
struct node
{
int data ;
struct node *next ;
} ;
struct node *first=NULL ;
struct node *last=NULL ;
void create()
{
int i , n ;
struct node *pnode , *p ;
printf("Enter the number of nodes required:\n") ;
scanf("%d",&n) ;
printf("Enter the data value of each node:\n") ;
for(i=1 ; i<=n ; i++)
{
pnode=(struct node*)malloc(sizeof(struct node)) ;
if(pnode==NULL)
{
printf("Memory overflow. Unable to create.\n") ;
return ;
}
scanf("%d",&pnode->data) ;
if(first==NULL)
first=last=pnode ;
else
{
last->next=pnode ;
last=pnode ;
}
last->next=first ;
}
}
void deletenode(int k)
{
struct node *p , *follow ;
p=first ;
follow=NULL ;
while(follow!=last)
{
if(p->data==k)
break ;
follow=p ;
p=p->next ;
}
if(follow==last)
printf("Required node not found.\n") ;
else
{
if(p==first&&p==last)
first=last=NULL ;
else if(p==first)
{
first=first->next ;
last->next=first ;
}
else if(p==last)
{
last=follow ;
last->next=first ;
}
else
follow->next=p->next ;
free(p) ;
}
}
void traverse()
{
struct node *p , *follow ;
if(first==NULL)
printf("Circularly Linked List Empty") ;
else
{
printf("Circularly Linked List is as shown: \n") ;
p=first ;
follow = NULL ;
while(follow!=last)
{
printf("%d " , p->data) ;
follow=p ;
p=p->next ;
}
printf("\n") ;
}
}
int main()
{
int x , k , ch ;
do
{
printf("\n Menu: \n") ;
printf("1:Create Linked List \n") ;
printf("2:Delete Node \n") ;
printf("3:Traverse \n") ;
printf("4:Exit \n") ;
printf("\nEnter your choice: ") ;
scanf("%d",&ch) ;
switch(ch)
{
case 1:
create() ;
break ;
case 2:
printf("Enter the data value of the node to be deleted: ") ;
scanf("%d",&k) ;
deletenode(k) ;
break ;
case 3:
traverse() ;
break ;
case 4:
break ;
}
}
while(ch!=4) ;
return 0;
}