Exchange Nodes

Problem: Exchange the odd and even nodes in a linked list.

Given a "head" pointer to a linked list. You are asked to write a C/C++ function to exchange the odd and even nodes in the linked list. For example:

Please follow the type and function definitions below:

typedef struct _Node...{    int value;    struct _Node* next;}Node;void ExchangeNodes(Node** phead) //note: phead is of Node** type...{    //your code here.}

Here is my solution, however I have made a little change to make it look like in a C++ style.

#include <iostream>

class Node

{

public:

       int value;

       Node* next;

public:

       static void ExchangeNodes( Node** );

};

void Node::ExchangeNodes(Node** phead)

{

       Node* p1 = *phead;

       Node* p2;

       int tval;

       while( p1 )

       {

              p2 = p1->next;

              if ( !p2 )

                     break;

              tval = p1->value;

              p1->value = p2->value;

              p2->value = tval;

              p1 = p2->next;

       }

}

 

 

// Here is the test code

int main( int argc, char* argv[] )

{

       Node* head;

       Node* tail;

       Node* iter;

       head = new Node;

       head->value = 1;

       head->next = NULL;

       tail = head;

       for ( int i = 2; i < 8; i++ )

       {

              iter = new Node;

              iter->value = i;

              iter->next = NULL;

              tail->next = iter;

              tail = iter;

       }

       for( iter = head; iter != NULL; iter = iter->next )

       {

              std::cout << iter->value << std::endl;

       }

       Node::ExchangeNodes( &head );

 

 

       std::cout<< "--------------------" << std::endl;

       for( iter = head; iter != NULL; iter = iter->next )

       {

              std::cout << iter->value << std::endl;

       }    

       return 0;

}

output:

1
2
3
4
5
6
7
--------------------
2
1
4
3
6
5
7