﻿ C : Delete a node from the middle of a circular linked list

# C Exercises: Delete a node from the middle of a circular linked list

## C Doubly Linked List : Exercise-17 with Solution

Write a program in C to delete a node from the middle of a circular linked list.

Visual Presentation:

Sample Solution:

C Code:

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

// Structure definition for a node in a circular linked list
struct node {
int num;
struct node *nextptr;
} *stnode;

struct node *tail, *p, *q, *store;

// Function prototypes
void ClListcreation(int n);
void ClListDeleteMiddle(int pos);
void displayClList(int a);

int main() {
int n, num1, a, pos;
stnode = NULL;

// User input for the number of nodes
printf("\n\n Circular Linked List : Delete node from the middle of a circular linked list :\n");
printf("-----------------------------------------------------------------------------------\n");
printf(" Input the number of nodes : ");
scanf("%d", &n);

// Creating a circular linked list
ClListcreation(n);
a = 1;
displayClList(a);

// User input for the position to delete a node
printf("\n Input the position to delete the node : ");
scanf("%d", &pos);
ClListDeleteMiddle(pos);
a = 2;
displayClList(a);

return 0;
}

// Function to create a circular linked list
void ClListcreation(int n) {
int i, num;
struct node *preptr, *newnode;

if (n >= 1) {
stnode = (struct node *)malloc(sizeof(struct node));

// Input for the first node
printf(" Input data for node 1 : ");
scanf("%d", &num);
stnode->num = num;
stnode->nextptr = NULL;
preptr = stnode;

// Loop to create subsequent nodes and link them to form a circular list
for (i = 2; i <= n; i++) {
newnode = (struct node *)malloc(sizeof(struct node));
printf(" Input data for node %d : ", i);
scanf("%d", &num);
newnode->num = num;
newnode->nextptr = NULL;
preptr->nextptr = newnode;
preptr = newnode;
}
preptr->nextptr = stnode; // Last node linking with the first node to form a circular list
}
}

// Function to delete a node from the middle of the circular linked list
void ClListDeleteMiddle(int pos) {
int delNode, k = 1;
delNode = pos;
p = stnode;

// Traversing to the specified position
while (k != delNode) {
q = p;
p = p->nextptr;
k++;
}

// Removing the node at the specified position
q->nextptr = p->nextptr;
printf("\n The deleted node is : %d", p->num);
free(p);
}

// Function to display the circular linked list
void displayClList(int m) {
struct node *tmp;
int n = 1;

if (stnode == NULL) {
printf(" No data found in the List yet.");
} else {
tmp = stnode;
if (m == 1) {
printf("\n Data entered in the list are :\n");
} else {
printf("\n After deletion the new list are :\n");
}

// Loop to display nodes in the circular list
do {
printf(" Data %d = %d\n", n, tmp->num);
tmp = tmp->nextptr;
n++;
} while (tmp != stnode);
}
}
```
```

Sample Output:

``` Circular Linked List : Delete node from the middle of a circular linked list :
-----------------------------------------------------------------------------------
Input the number of nodes : 3
Input data for node 1 : 2
Input data for node 2 : 5
Input data for node 3 : 8

Data entered in the list are :
Data 1 = 2
Data 2 = 5
Data 3 = 8

Input the position to delete the node : 3

The deleted node is : 8
After deletion the new list are :
Data 1 = 2
Data 2 = 5
```

Flowchart:

ClListcreation() :

ClListDeleteMiddle() :

displayClList() :

C Programming Code Editor:

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

﻿