Print alternate nodes of a linked list without using recursion in C

In this tutorial, we will learn how to print alternate nodes of a linked list without using recursion with the help of the C program? By Piyas Mukherjee Last updated : August 02, 2023

Input

A singly linked list whose address of the first node is stored in a pointer, say head

Output

The alternative nodes in the list

Data Structure Used

Singly linked list where each node contains a data element say data, and the address of the immediate next node say next, with Head holding the address of the first node.

Pseudo Code

Function alternatedisplay()
    Begin
        print "Displaying the alternative items of 
                the list starting from the beginning"
        temp=head //initialize
        While(temp!=NULL)
            Begin
            print "temp->data"
            If(temp->next==NULL)	
                temp=NULL
            Else
                temp=temp->next->next; //jump to second next one
            End If
        End While
End Function

C program to print alternate nodes of a linked list without using recursion

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

//node structure
typedef struct list {
    int data;
    struct list* next;
} node;

void alternatedisp(node* temp);

int main()
{
    node *head = NULL, *temp, *temp1;
    int choice, count = 0, key;

    //Taking the linked list as input
    do {
        temp = (node*)malloc(sizeof(node));
        if (temp != NULL) {
            printf("\nEnter the element in the list : ");
            scanf("%d", &temp->data);
            temp->next = NULL;
            if (head == NULL) {
                head = temp;
            }
            else {
                temp1 = head;
                while (temp1->next != NULL) {
                    temp1 = temp1->next;
                }
                temp1->next = temp;
            }
        }
        else {
            printf("\nMemory not avilable...node allocation is not possible");
        }
        printf("\nIf you wish to add m ore data on the list enter 1 : ");
        scanf("%d", &choice);
    } while (choice == 1);

    //Now displaying the alternative nodes starting from the begining
    alternatedisp(head);

    return 0;
}

void alternatedisp(node* temp)
{
    printf("\nDisplaying the alternative items of the list starting from the begining : \n");
    while (temp != NULL) {
        printf("%d ", temp->data);
        //check for end of list
        if (temp->next == NULL)
            temp = NULL;
        else
            //jump to second next skipping immediate one
            temp = temp->next->next;
    }
}

Output

Enter the element in the list : 1

If you wish to add m ore data on the list enter 1 : 1

Enter the element in the list : 2

If you wish to add m ore data on the list enter 1 : 1

Enter the element in the list : 3

If you wish to add m ore data on the list enter 1 : 1

Enter the element in the list : 4

If you wish to add m ore data on the list enter 1 : 1

Enter the element in the list : 5

If you wish to add m ore data on the list enter 1 : 0

Displaying the alternative items of the list starting from the begining :
1 3 5