Insertion in circular linked list: Beginning and End

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🧑‍💻 By quescol • 📝 Updated on: 10 May 2025

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Insert a node in Beginning of circular linked list

#include<stdio.h> 
#include<conio.h>
#include<stdlib.h>
struct node{
	int data;
	struct node *next;
	};
struct node *head=NULL;
struct node* createNode(){
	struct node *newNode = (struct node *)malloc(sizeof(struct node));
    return (newNode);
    }

void insertNodeAtBegin(){
    struct node *newNode, *temp, *ptr1, *ptr2;
    newNode=createNode();
    printf("Enter a data to insert at begining:");
    scanf("%d",&newNode->data);
    newNode->next=NULL;
    if(head==NULL){
	    head=newNode;
	    head->next=head;
    }
    else{
	    ptr1=head;
	    ptr2=head;
	    while(ptr1->next!=head){
		    ptr1=ptr1->next;
	    }
	    ptr1->next=newNode;
	    head=newNode;
	    head->next=ptr2;
    }
}

void viewList(){
	struct node* temp=head;
	if(temp==NULL){
		printf("list is empty");
	}
	else{
	    printf("Data in circular linked list are:\n");
		while(temp->next!=head)
		{
			printf("%d\t",temp->data);
			temp=temp->next;
		}
		printf("%d \t",temp->data);
	}
}

int menu(){
    int choice;
    printf("\n 1. Insert at begining");
    printf("\n 2. Travesre/View List");
    printf("\n 3. exit");
    printf("\n Please enter your choice: \t");
    scanf("%d",&choice);
    return(choice);
}
 void main(){
    printf("Insert a node in Beginning of circular linked list"); 
    while(1){
        switch(menu()){
            case 1:
                insertNodeAtBegin();
                break;
            case 2:
                viewList();
                break;
            case 3:
                exit(0);
            default:
                printf("invalid choice");   
        }
        getch();
    }  
}

Output:

Insert a node in Beginning of circular linked list
 1. Insert at begining
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at begining:4

 1. Insert at begining
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at begining:7

 1. Insert at begining
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at begining:9

 1. Insert at begining
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at begining:5

 1. Insert at begining
 2. Travesre/View List
 3. exit
 Please enter your choice:      2
Data in circular linked list are:
5       9       7       4 
 1. Insert at begining
 2. Travesre/View List
 3. exit
 Please enter your choice:      3

Insert a node at end of Circular Linked list 

#include<stdio.h> 
#include<conio.h>
#include<stdlib.h>
struct node{
	int data;
	struct node *next;
	};
struct node *head=NULL;
struct node* createNode(){
	struct node *newNode = (struct node *)malloc(sizeof(struct node));
    return (newNode);
    }

void insertNodeAtEnd(){
	struct node *temp,*ptr;
	temp=createNode();
	printf("Enter a data to insert at end:");
	scanf("%d",&temp->data);
	temp->next=NULL;
	if(head==NULL){
		head=temp;
		head->next=head;
	}
	else{
		ptr=head;
		while(ptr->next!=head){
			ptr=ptr->next;
		}
	    ptr->next=temp;
	    temp->next=head;
	}
}

void viewList(){
	struct node* temp=head;
	if(temp==NULL){
		printf("list is empty");
	}
	else{
	    printf("Data in circular linked list are:\n");
		while(temp->next!=head)
		{
			printf("%d\t",temp->data);
			temp=temp->next;
		}
		printf("%d \t",temp->data);
	}
}

int menu(){
    int choice;
    printf("\n 1. Insert at end");
    printf("\n 2. Travesre/View List");
    printf("\n 3. exit");
    printf("\n Please enter your choice: \t");
    scanf("%d",&choice);
    return(choice);
}
 void main(){
    printf("Insert a node at end of Circular Linked list");
    while(1){
        switch(menu()){
            case 1:
                insertNodeAtEnd();
                break;
            case 2:
                viewList();
                break;
            case 3:
                exit(0);
            default:
                printf("invalid choice");   
        }
        getch();
    }  
}

Output:

Insert a node at end of Circular Linked list
 1. Insert at end
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at end:4

 1. Insert at end
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at end:6

 1. Insert at end
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at end:3

 1. Insert at end
 2. Travesre/View List
 3. exit
 Please enter your choice:      1
Enter a data to insert at end:2

 1. Insert at end
 2. Travesre/View List
 3. exit
 Please enter your choice:      2
Data in circular linked list are:
4       6       3       2 
 1. Insert at end
 2. Travesre/View List
 3. exit
 Please enter your choice:      3

Insert a node at a given position in Circular Linked List

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

struct node {
    int data;
    struct node *next;
};

struct node *head = NULL;

struct node* createNode() {
    struct node *newNode = (struct node *)malloc(sizeof(struct node));
    return newNode;
}

void insertNodeAtEnd() {
    struct node *temp, *ptr;
    temp = createNode();
    printf("Enter a data to insert at end: ");
    scanf("%d", &temp->data);
    temp->next = NULL;

    if (head == NULL) {
        head = temp;
        head->next = head;
    } else {
        ptr = head;
        while (ptr->next != head) {
            ptr = ptr->next;
        }
        ptr->next = temp;
        temp->next = head;
    }
}

void insertNodeAtLocation() {
    int pos, i = 1;
    struct node *temp, *ptr;
    temp = createNode();
    printf("Enter position to insert: ");
    scanf("%d", &pos);
    printf("Enter data to insert at position %d: ", pos);
    scanf("%d", &temp->data);
    temp->next = NULL;

    if (pos == 1) {
        if (head == NULL) {
            head = temp;
            head->next = head;
        } else {
            ptr = head;
            while (ptr->next != head) {
                ptr = ptr->next;
            }
            temp->next = head;
            head = temp;
            ptr->next = head;
        }
    } else {
        ptr = head;
        while (i < pos - 1 && ptr->next != head) {
            ptr = ptr->next;
            i++;
        }
        if (i == pos - 1) {
            temp->next = ptr->next;
            ptr->next = temp;
        } else {
            printf("Invalid position!\n");
            free(temp);
        }
    }
}

void viewList() {
    struct node* temp = head;
    if (temp == NULL) {
        printf("List is empty\n");
    } else {
        printf("Data in circular linked list are:\n");
        while (temp->next != head) {
            printf("%d\t", temp->data);
            temp = temp->next;
        }
        printf("%d\t", temp->data);
    }
}

int menu() {
    int choice;
    printf("\n--- MENU ---");
    printf("\n1. Insert at end");
    printf("\n2. Insert at a given location");
    printf("\n3. Traverse/View List");
    printf("\n4. Exit");
    printf("\nEnter your choice: ");
    scanf("%d", &choice);
    return choice;
}

void main() {
    printf("Insertion in Circular Linked List\n");
    while (1) {
        switch (menu()) {
            case 1:
                insertNodeAtEnd();
                break;
            case 2:
                insertNodeAtLocation();
                break;
            case 3:
                viewList();
                break;
            case 4:
                exit(0);
            default:
                printf("Invalid choice\n");
        }
        getch();
    }
}

Output:

Insertion in Circular Linked List

--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 1
Enter a data to insert at end: 4

--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 1
Enter a data to insert at end: 6

--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 1
Enter a data to insert at end: 8

--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 1
Enter a data to insert at end: 3

--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 3
Data in circular linked list are:
4       6       8       3
--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 2
Enter position to insert: 2
Enter data to insert at position 2: 8

--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 3
Data in circular linked list are:
4       8       6       8       3
--- MENU ---
1. Insert at end
2. Insert at a given location
3. Traverse/View List
4. Exit
Enter your choice: 3

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