REVERSE A Doubly LinkList

#include"stdio.h'
#include'ctype.h"
typedef struct node
{
int value;
struct node *next;
struct node *prev;
}mynode ;
mynode *head, *tail;
void add_node(int value);
void print_list();
void reverse();
int main()
{
head=NULL;
tail=NULL;
add_node(1);
add_node(2);
add_node(3);
add_node(4);
add_node(5);
print_list();
reverse();
print_list();
return(1);
}
void add_node(int value)
{
mynode *temp, *cur;
temp = (mynode *)malloc(sizeof(mynode));
temp->next=NULL;
temp->prev=NULL;
if(head == NULL)
{
printf("\nAdding a head pointer\n");
head=temp;
tail=temp;
temp->value=value;
}
else
{
for(cur=head;cur->next!=NULL;cur=cur->next);
cur->next=temp;
temp->prev=cur;
temp->value=value;
tail=temp;
}
}
void print_list()
{
mynode *temp;
printf("\n--------------------------------\n");
for(temp=head;temp!=NULL;temp=temp->next)
{
printf("\n[%d]\n",temp->value);
}
}
void reverse()
{
mynode *cur, *temp, *save_next;
if(head==tail)return;
if(head==NULL || tail==NULL)return;
for(cur=head;cur!=NULL;)
{
printf("\ncur->value : [%d]\n",cur->value);
temp=cur->next;
save_next=cur->next;
cur->next=cur->prev;
cur->prev=temp;
cur=save_next;
}
temp=head;
head=tail;
tail=temp;
}