Interchange the two adjacent nodes in a given circular linked list | C program

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mahmoud2506

2022-05-08

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Data structure used: Circular 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 and the next part of the last node contains head.

Pseudo code:

//assumed all node has different key, so searching node by key value
temp=head;
while(temp->data!=key)
    begin
    temp1=temp
    temp=temp->next
End while

//node found which is to be interchanged
IF(temp=head)
    temp1=temp->next
    temp->next=temp1->next
    temp1->next=temp
    head=temp1
ELSE			
    temp2=temp->next
    temp->next=temp2->next
    temp2->next=temp
    temp1->next=temp2
End IF-ELSE
End

C code:

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

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

void display(node *temp)
{
	node *temp1=temp;
	printf("\nNow the list is :\n%d->",temp->data);
	temp=temp->next;
	while(temp!=temp1)	
	{
		printf("%d->",temp->data);
		temp=temp->next;
	}
	printf("%d\n",temp1->data);
}

int main(){
	node *head=NULL,*temp,*temp1,*temp2;
	int choice,key;
	
	do
	{
		temp=(node *)malloc(sizeof(node));
		if(temp!=NULL)
		{
			printf("\nEnter the element in the list : ");
			scanf("%d",&temp->data);
			if(head==NULL)
			{	
				head=temp;
			}
			else
			{
				temp1=head;
				while(temp1->next!=head)
				{
					temp1=temp1->next;
				}
				temp1->next=temp;
			}
			temp->next=head;
		}
		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);
	
	display(head);
	printf("\nEnter the data of the node which you want to exchange with it's next : ");
	scanf("%d",&key);
	temp=head;
	while(temp->data!=key)
	{
		temp1=temp;
		temp=temp->next;
	}
	if(temp==head)
	{
		temp1=temp->next;
		temp->next=temp1->next;
		temp1->next=temp;
		head=temp1;
	}
	else
	{
		temp2=temp->next;
		temp->next=temp2->next;
		temp2->next=temp;
		temp1->next=temp2;
	}
	
	display(head);
	
	return 0;
}

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

Now the list is :
1->2->3->4->5->1

Enter the data of the node which you want to exchange with it's next : 3

Now the list is :
1->2->4->3->5->1

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total answers (1)

Interchange the two adjacent nodes in a given circular linked list | C program

Interchange the two adjacent nodes in a given circular linked list | C program

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Data Structure programs using C and C++ (Linked List Programs)

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