C Exercises: Remove elements with even indices from a linked list
C Singly Linked List : Exercise-26 with Solution
Write a C program that removes elements with even indices from a singly linked list.
Sample Solution:
C Code:
#include<stdio.h>
#include <stdlib.h>
// Definition for singly-linked list.
struct Node {
int data;
struct Node* next;
};
// Function to remove elements with even indices from a linked list
void remove_Even_indices(struct Node** head) {
struct Node* current = *head; // Pointer to traverse the list
struct Node* prev = NULL; // Pointer to track the previous node
int count = 0; // Variable to track the index of nodes, starting from 0
// Traverse the linked list
while (current != NULL) {
if (count % 2 == 0) { // Check if the index is even
if (prev == NULL) {
*head = current->next; // Update head if the even index is the head node
} else {
prev->next = current->next; // Skip the node at even index
}
struct Node* temp = current; // Store the current node to free it later
current = current->next; // Move to the next node
free(temp); // Free the memory of the removed node
} else {
prev = current; // Move the 'prev' pointer to the current node
current = current->next; // Move to the next node
}
count++; // Increment the index count
}
}
// Function to insert a new node at the beginning of the linked list
void push(struct Node** head, int data) {
struct Node* new_node = (struct Node*) malloc(sizeof(struct Node)); // Allocate memory for a new node
new_node->data = data; // Assign data to the new node
new_node->next = *head; // Set the next of the new node to the current head
*head = new_node; // Update the head to point to the new node
}
// Function to print the linked list
void printList(struct Node* head) {
while (head != NULL) { // Iterate through the linked list
printf("%d ", head->data); // Print the data of the current node
head = head->next; // Move to the next node
}
printf("\n"); // Print a new line after printing all nodes
}
// Test function to demonstrate the removal of even-indexed elements
int main() {
struct Node* head = NULL; // Initialize an empty linked list
// Create a linked list with some initial values
push(&head, 1);
push(&head, 2);
push(&head, 3);
push(&head, 4);
push(&head, 5);
push(&head, 6);
push(&head, 7);
printf("Original linked list:\n");
printList(head); // Display the original linked list
remove_Even_indices(&head); // Call function to remove even-indexed elements
printf("\nLinked list after removing even indices:\n");
printList(head); // Display the modified linked list after removal
return 0; // Indicate successful completion of the program
}
Sample Output:
Original linked list: 7 6 5 4 3 2 1 Linked list after removing even indices: 6 4 2
Flowchart :
C Programming Code Editor:
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