Reversing a double linked link - non recursive

[sports528]

I am trying to reverse a double linked list, but keep getting seg faults, infinite loops, or just my first term (after being reversed). I am trying to switch the next and prev pointers between two nodes, then switch head and tail.

Can someone help? all other functions work (size(), etc.)

My files/code is as follows:

in list.cpp

List::List() {
head = NULL;
tail = NULL;
}

void List::reverse(void) {

Node *cur = head;
Node *temp,*temp2,*temp3;
List *ltemp = new List();

if (size() > 1) {

// for (int i = 0;i < size()-1;i++) {
while (cur->next != NULL) {
temp=cur->next;
temp2 = cur->next->prev;

temp3 = temp;
temp = temp2;
temp2 = temp3;
//cur->next->prev=temp;
//cur->next = temp2;

cur = cur->next;
}
//switching last node
cur=tail;
cur->next=head;
cur->prev=NULL;

temp = head;
head = tail;
tail = temp;
}
}

in node.cpp

#include "node.h"
#define NULL 0

extern Node *next;
extern Node *prev;

Node::Node(int num) {
data = num;
next = NULL;
prev = NULL;
}

[sports528]

Sorry, i just figured it out.

The function code is as follows:

void List::reverse(void) {

Node *cur = head;
Node *temp,*save_next;

if(head==tail)return;
if(head==NULL || tail==NULL)return;
for(cur=head;cur!=NULL;)
{

temp=cur->next;
save_next=cur->next;
cur->next=cur->prev;
cur->prev=temp;
cur=save_next;
}

temp=head;
head=tail;
tail=temp;
}