C program to print the even elements of the linked list

In this tutorial, we will learn how to print the even elements of the linked list using the C program? By Nidhi Last updated : August 02, 2023

Problem statement

Given a singly linked list, we have to print the even elements.

C program to print the even elements of the linked list

The source code to print the EVEN elements of the linked list is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

// C program to print the even elements
// of linked list

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

//Self-referential structure to create the node.
typedef struct tmp {
    int item;
    struct tmp* next;
} Node;

//structure for creating the linked list.
typedef struct
    {
    Node* head;
    Node* tail;

} List;

//Initialize List
void initList(List* lp)
{
    lp->head = NULL;
    lp->tail = NULL;
}

//Create node and return the reference of it.
Node* createNode(int item)
{
    Node* nNode;

    nNode = (Node*)malloc(sizeof(Node));

    nNode->item = item;
    nNode->next = NULL;

    return nNode;
}

//Add a new item at the end of the list.
void addAtTail(List* lp, int item)
{
    Node* node;
    node = createNode(item);

    //if list is empty.
    if (lp->head == NULL) {
        lp->head = node;
        lp->tail = node;
    }
    else {
        lp->tail->next = node;
        lp->tail = lp->tail->next;
    }
}

//Add a new item at the beginning of the list.
void addAtHead(List* lp, int item)
{
    Node* node;
    node = createNode(item);

    //if list is empty.
    if (lp->head == NULL) {
        lp->head = node;
        lp->tail = node;
    }
    else {
        node->next = lp->head;
        lp->head = node;
    }
}

//To print the list from start to end of the list.
void printList(List* lp)
{
    Node* node;

    if (lp->head == NULL) {
        printf("\nEmpty List");
        return;
    }

    node = lp->head;

    while (node != NULL) {
        printf("| %05d |", node->item);
        node = node->next;

        if (node != NULL)
            printf("--->");
    }
    printf("\n\n");
}

void printEvens(List* lp)
{
    Node* temp;

    temp = lp->head;

    while (temp != NULL) {
        if (temp->item % 2 == 0)
            printf("%d ", temp->item);

        temp = temp->next;
    }
}

//Main function to execute program.
int main()
{
    List* lp;

    lp = (List*)malloc(sizeof(List));

    initList(lp);

    addAtHead(lp, 101);
    addAtHead(lp, 102);
    addAtHead(lp, 103);
    addAtHead(lp, 104);
    addAtHead(lp, 105);

    printf("List:\n");
    printList(lp);

    printf("Even elements: \n");
    printEvens(lp);

    printf("\n");

    return 0;
}

Output

List:
| 00105 |--->| 00104 |--->| 00103 |--->| 00102 |--->| 00101 |

Even elements: 
104 102

Explanation

Here, we created a self-referential structure to implement a linked list, a function to add a node at the start and end of the list, a function printEvens() to print elements of the linked list.

In the main() function, we created a linked list. Then we printed the even elements of the linked list on the console screen.