Circular Linked List Example

Single Circular Linked List

Example: A data structure program using C to create a Single Circular Linked List with user-defined nodes to store records with at least two attributes of student and then display all the stored records.

#include <stdio.h>  
#include <conio.h>  
#include <malloc.h>

struct number
{
  int num;    
  struct number *ptr;  
};
   
struct number *home, *link, *newnode;
	
void create(struct number *);
void display(struct number *);

int i,x;
   
void main()
{
   printf("Enter the Node value for a Single Circular Linked List = ");
   scanf("%d",&x);
   printf("Enter %d Integer Numeric Value = ",x);
   
   home= (struct number*)malloc(sizeof(struct number));   
   scanf("%d",&home->num);
   home->ptr=home;
   
   create(home);
   display(home);
   
   getch();
}

void create(struct number *home1)
{
   link=home1;   
   int i;	   
   for(i=1;i<x;i++)
   {
     newnode= (struct number*)malloc(sizeof(struct number));
     printf("Enter Integer Numeric Value = ");
     scanf("%d",&newnode->num);
     newnode->ptr=home;
			
     link->ptr=newnode;
     link=link->ptr;			
   }
}

// Traversing or Printing code for Single Circular Linked List  
void display(struct number *home2)
{
   printf("\nThe Outputs are = \n");
   link=home2;
   do
    {
   	printf("%d ",link->num);	
	link=link->ptr;   	
    }while(link!=home);         
}
             OR
void display(struct number *home2)
{
   printf("\nThe Outputs are = \n");
   link=home2;
   newnode=NULL;
   while(link!=newnode)
    {
   	printf("%d ",link->num);	
	link=link->ptr;
	newnode=home;   	
    }         
}
                OR
void display(struct number *home2)
{
   	printf("\nThe Outputs are = \n");   
   	link=home2;
   	
   	printf("%d ",link->num);	
	link=link->ptr;
   
   while(link!=home2)
     {
   	printf("%d ",link->num);	
	link=link->ptr;		   	
     }         
}

Output:
Enter the Node value for a Single Circular Linked List = 4
Enter 4 Integer Numeric Value = 10
Enter Integer Numeric Value = 20
Enter Integer Numeric Value = 30
Enter Integer Numeric Value = 40

The Outputs are =
10 20 30 40

Example: A data structure program using C to Insert a new node into a Single Circular Linked List at the Beginning with the user-defined existing nodes and then display all the records.

#include <stdio.h>  
#include <conio.h>  
#include <malloc.h>

struct number
{
  int num;    
  struct number *ptr;  
};
   
struct number *home, *link, *newnode;
	
void create(struct number *);
void display(struct number *);
void addatbeg(struct number *);

int i,x;
   
void main()
{
   	printf("Enter the Node value for a Single Circular Linked List = ");
   	scanf("%d",&x);
   	printf("Enter %d Integer Numeric Value = ",x);
   
   	home= (struct number*)malloc(sizeof(struct number));   
   	scanf("%d",&home->num);
   	home->ptr=home;
   
   	create(home);
   	printf("\nThe output before Insertion at beginningare\n");
   	display(home);
   	
   	addatbeg(home);
   	printf("\nThe output after Insertion at beginning are\n");
  	display(home);
   
   getch();
}

void create(struct number *home1)
{
   link=home1;   
   int i;	   
   for(i=1;i<x;i++)
   {
     newnode= (struct number*)malloc(sizeof(struct number));
     printf("Enter Integer Numeric Value = ");
     scanf("%d",&newnode->num);
     newnode->ptr=home;
			
     link->ptr=newnode;
     link=link->ptr;			
   }
}

void addatbeg(struct number *home3)
{
    link=home3;		 
		
	while(link->ptr!=home)	
	{
	  link=link->ptr;
	} 		
   
    newnode=(struct number*)malloc(sizeof(struct number));
    printf("\n\nEnter Single Integer Numeric Value for Insertion = ");
    scanf("%d",&newnode->num);    
    newnode->ptr=newnode;
    
    newnode->ptr=home;		    
    home=newnode;	
		
    link->ptr=home;					
}
   
void display(struct number *home2)
{   
   link=home2;
   do
     {
   	printf("%d ",link->num);	
	link=link->ptr;   	
     }while(link!=home);         
}

Output:
Enter the Node value for a Single Circular Linked List = 4
Enter 4 Integer Numeric Value = 10
Enter Integer Numeric Value = 20
Enter Integer Numeric Value = 30
Enter Integer Numeric Value = 40

The output before Insertion at beginning are
10 20 30 40

Enter Single Integer Numeric Value for Insertion = 50

The output after Insertion at beginning are
50 10 20 30 40

Example: A data structure program using C to Insert a new node into a Single Circular List at the End with the user-defined existing nodes and then display all the records.

#include <stdio.h>  
#include <conio.h>  
#include <malloc.h>

struct number
{
  int num;    
  struct number *ptr;  
};
   
struct number *home, *link, *newnode;
	
void create(struct number *);
void display(struct number *);
void addatend(struct number *);

int i,x;
   
void main()
{
   	printf("Enter the Node value for a Single Circular Linked List = ");
   	scanf("%d",&x);
   	printf("Enter %d Integer Numeric Value = ",x);
   
   	home= (struct number*)malloc(sizeof(struct number));   
   	scanf("%d",&home->num);
   	home->ptr=home;
   
   	create(home);
   	printf("\nThe output before Insertion at the End are\n");
   	display(home);
   	
   	addatend(home);
   	printf("\nThe output after Insertion at the End are\n");
  	display(home);
   
   getch();
}

void create(struct number *home1)
{
   link=home1;   
   int i;	   
   for(i=1;i<x;i++)
   {
     newnode= (struct number*)malloc(sizeof(struct number));
     printf("Enter Integer Numeric Value = ");
     scanf("%d",&newnode->num);
     newnode->ptr=home;
			
     link->ptr=newnode;
     link=link->ptr;			
   }
}

void addatend(struct number *home3)
{
   link=home3;		 
		
	while(link->ptr!=home)	
	{
	   link=link->ptr;
	} 		
   
    newnode=(struct number*)malloc(sizeof(struct number));
    printf("\n\nEnter Single Integer Numeric Value for Insertion = ");
    scanf("%d",&newnode->num);    
    newnode->ptr=home;   
		
    link->ptr=newnode;					
}
   
void display(struct number *home2)
{   
   link=home2;
   do
     {
   	printf("%d ",link->num);	
	link=link->ptr;   	
     }while(link!=home);         
}

Output:
Enter the Node value for a Single Circular Linked List = 3
Enter 3 Integer Numeric Value = 10
Enter Integer Numeric Value = 20
Enter Integer Numeric Value = 30

The output before Insertion at the End are
10 20 30

Enter Single Integer Numeric Value for Insertion = 40

The output after Insertion at the End are
10 20 30 40

Example: A data structure program using C to Delete a node from a Single Circular List from the Beginning with the user-defined existing nodes and then display all the records.

#include <stdio.h>  
#include <conio.h>  
#include <malloc.h>

struct number
{
  int num;    
  struct number *ptr;  
};
   
struct number *home, *link, *newnode;
	
void create(struct number *);
void display(struct number *);
void delatbeg(struct number *);

int i,x;
   
void main()
{
   	printf("Enter the Node value for a Single Circular Linked List = ");
   	scanf("%d",&x);
   	printf("Enter %d Integer Numeric Value = ",x);
   
   	home= (struct number*)malloc(sizeof(struct number));   
   	scanf("%d",&home->num);
   	home->ptr=home;
   
   	create(home);
   	printf("\nThe output before Deletion from the Beginning are\n");
   	display(home);
   	
   	delatbeg(home);
   	printf("\nThe output after Deletion from the Beginning are\n");
  	display(home);
   
   getch();
}

void create(struct number *home1)
{
   link=home1;   
   int i;	   
   for(i=1;i<x;i++)
   {
     newnode= (struct number*)malloc(sizeof(struct number));
     printf("Enter Integer Numeric Value = ");
     scanf("%d",&newnode->num);
     newnode->ptr=home;
			
     link->ptr=newnode;
     link=link->ptr;			
   }
}

void delatbeg(struct number *home3)
{
   link=home3;
   while(link->ptr!=home)	
     {
	link=link->ptr;
     } 		
   
   newnode=home3;   
   home=home->ptr;
   link->ptr=home;
		
   free(newnode);					
}
   
void display(struct number *home2)
{   
   link=home2;
   do
     {
   	printf("%d ",link->num);	
	link=link->ptr;   	
     }while(link!=home);         
}

Output:
Enter the Node value for a Single Circular Linked List = 4
Enter 4 Integer Numeric Value = 10
Enter Integer Numeric Value = 20
Enter Integer Numeric Value = 30
Enter Integer Numeric Value = 40

The output before Deletion from the Beginning are
10 20 30 40
The output after Deletion from the Beginning are
20 30 40

Example: A data structure program using C to Delete a node from a Single Circular List from the End with the user-defined existing nodes and then display all the records.

#include <stdio.h>  
#include <conio.h>  
#include <malloc.h>

struct number
{
  int num;    
  struct number *ptr;  
};
   
struct number *home, *link, *newnode;
	
void create(struct number *);
void display(struct number *);
void delatend(struct number *);

int i,x;
   
void main()
{
   	printf("Enter the Node value [>3] for a Single Circular Linked List = ");
   	scanf("%d",&x);
   	printf("Enter %d Integer Numeric Value = ",x);
   
   	home= (struct number*)malloc(sizeof(struct number));   
   	scanf("%d",&home->num);
   	home->ptr=home;
   
   	create(home);
   	printf("\nThe output before Deletion from the End are\n");
   	display(home);
   	
   	delatend(home);
   	printf("\nThe output after Deletion from the End are\n");
  	display(home);
   
  getch();
}

void create(struct number *home1)
{
   link=home1;   
   int i;	   
   for(i=1;i<x;i++)
   {
     newnode= (struct number*)malloc(sizeof(struct number));
     printf("Enter Integer Numeric Value = ");
     scanf("%d",&newnode->num);
     newnode->ptr=home;
			
     link->ptr=newnode;
     link=link->ptr;			
   }
}

void delatend(struct number *home3)
{
   link=home3;		
   while(link->ptr->ptr!=home)	
     {
	link=link->ptr;
     } 		
   
   newnode=link->ptr;    
   link->ptr=home;
		
   free(newnode);					
}
   
void display(struct number *home2)
{   
   link=home2;
   do
     {
   	printf("%d ",link->num);	
	link=link->ptr;   	
     }while(link!=home);         
}

Output:
Enter the Node value [>3] for a Single Circular Linked List = 5
Enter 5 Integer Numeric Value = 10
Enter Integer Numeric Value = 20
Enter Integer Numeric Value = 30
Enter Integer Numeric Value = 40
Enter Integer Numeric Value = 50

The output before Deletion from the End are
10 20 30 40 50
The output after Deletion from the End are
10 20 30 40

Double Circular Linked List