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Print the Alternate Nodes in a Linked List without using Recursion
In this article, we are going to see how to print alternative nodes of a linked list from the beginning without using recursion?
Submitted by Piyas Mukherjee, on January 29, 2019
Solution:
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.
Pseudocode:
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 Implementation:
#include <stdio.h>
#include <stdlib.h>
typedef struct list //node structure
{
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