Write a C Program to Swap adjacent elements in a singly linked list

By | March 30, 2017

C Program to Swap adjacent elements in a singly linked list


Write a C Program to Swap adjacent elements in a singly linked list. Here’s simple Program to Swap adjacent elements in a singly linked list in C Programming Language.


What is Linked List ?


Linked list is a linear data structure that contains sequence of elements such that each element links to its next element in the sequence. Each link contains a connection to another link.

Following are the important terms to understand the concept of Linked List.

  • Link − Each link of a linked list can store a data called an element.
  • Next − Each link of a linked list contains a link to the next link called Next.

Each element in a linked list is called as “Node”. Each node consists of its own data and the address of the next node and forms a chain. Linked Lists are used to create trees and graphs.


Below is the source code for C Program to Swap adjacent elements in a singly linked list which is successfully compiled and run on Windows System to produce desired output as shown below :


SOURCE CODE : :


/* C Program to Swap adjacent elements in a singly linked list */

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

struct node
{
	int info;
	struct node *link;
};

struct node *create_list(struct node *start);
void display(struct node *start);
struct node *addatbeg(struct node *start,int data);
struct node *addatend(struct node *start,int data);
void SwapAdjacentInfo(struct node *start);
struct node *SwapAdjacent(struct node *start);

int main()
{
	struct node *start=NULL;
	start=create_list(start);
	display(start);
	start = SwapAdjacent(start);
	display(start);
	SwapAdjacentInfo(start);
	display(start);

	return 0;

}/*End of main()*/

void SwapAdjacentInfo(struct node *start)
{
	struct node *p,*q;
	int tmp;
	if(start==NULL || start->link==NULL) /*List empty or only one element in the list*/
		return;
	p=start;
	while(p!=NULL && p->link != NULL)
	{
		q=p->link;
		tmp = p->info;
		p->info = q->info;
		q->info = tmp;
		p=q->link;
	}
}/*End of SwapAdjacentInfo()*/

struct node *SwapAdjacent(struct node *start)
{
	struct node *r,*p,*q;
	if(start==NULL || start->link==NULL)/*List empty or only one element in the list*/
		return start;
	r=p=start;
	while(p->link!=NULL)
	{
		q=p->link;
		p->link=q->link;
		q->link=p;
		if(p!=start)
			r->link=q;
		else
			start=q;
		r=p;
		if(p->link!=NULL)
			p=p->link;
	}
	return start;
}/*End of SwapAdjacent()*/

struct node *create_list(struct node *start)
{
	int i,n,data;
	printf("Enter the number of nodes : ");
	scanf("%d",&n);
	start=NULL;
	if(n==0)
		return start;

	printf("Enter the element to be inserted : ");
	scanf("%d",&data);
	start=addatbeg(start,data);

	for(i=2;i<=n;i++)
	{
		printf("Enter the element to be inserted : ");
		scanf("%d",&data);
		start=addatend(start,data);
	}
	return start;
}/*End of create_list()*/

void display(struct node *start)
{
	struct node *p;
	if(start==NULL)
	{
		printf("List is empty\n");
		return;
	}
	p=start;
	printf("List is :\n");
	while(p!=NULL)
	{
		printf("%d ",p->info);
		p=p->link;
	}
	printf("\n\n");
}/*End of display() */

struct node *addatbeg(struct node *start,int data)
{
	struct node *tmp;
	tmp=(struct node *)malloc(sizeof(struct node));
	tmp->info=data;
	tmp->link=start;
	start=tmp;
	return start;
}/*End of addatbeg()*/

struct node *addatend(struct node *start,int data)
{
	struct node *p,*tmp;
	tmp=(struct node *)malloc(sizeof(struct node));
	tmp->info=data;
	p=start;
	while(p->link!=NULL)
		p=p->link;
	p->link=tmp;
	tmp->link=NULL;
	return start;
}/*End of addatend()*/


OUTPUT : :


/* C Program to Swap adjacent elements in a singly linked list */


************* OUTPUT ******************

Enter the number of nodes : 6
Enter the element to be inserted : 1
Enter the element to be inserted : 2
Enter the element to be inserted : 3
Enter the element to be inserted : 4
Enter the element to be inserted : 5
Enter the element to be inserted : 6
List is :
1 2 3 4 5 6

List is :
2 1 4 3 6 5

List is :
1 2 3 4 5 6

If you found any error or any queries related to the above program or any questions or reviews , you wanna to ask from us ,you may Contact Us through our contact Page or you can also comment below in the comment section.We will try our best to reach upto you in the short interval.


Thanks for reading the post….

Leave a Reply