how to reverse link list using recurtion

[happyshub]

please can someone give me code how to reverse single link list using recurtion

thanks

[Dave Sinkula]

please can someone give me code how to reverse single link list using recurtion

Show an attempt.

[happyshub]

Show an attempt.

Ohhh I am new to the forum and I was not knowing the rules :mrgreen: :p That I have to show attempt ...

Here is what I was trying to do ! :evil: :evil:

Without Recurtion :-)

struct node *p,*q,*r;
r=null;
p=head;
while(p)
{
    q=p->next;
    p->next=r;
    r=p;
    p=q;
}
head=p;

With recurtion :

list *tail;  
 
list *reverse (list *head)  
{  
  if (head->next == NULL)  
  {  
    tail = head;  
    return;  
  }else{  
    reverse (head->next);  
    head->next->next = head;  
    head->next = NULL;  
  }  
}

<< moderator edit: added [code][/code] tags >>

In general can we reverse link list using REFERERCNCE to pointer as function parameter .... :idea:

[Dogtree]

You're on the right track. Try incorporating a temporary link into your function rather than trying to work just with head and its next links.

[happyshub]

You're on the right track. Try incorporating a temporary link into your function rather than trying to work just with head and its next links.

Temperary variable to be passed in recursive function :evil: ??

temparary variable are temparary to scope of function and in recursive function we use global variable sort of things :rolleyes:

In general we can use static pointer but then toomit does not workk

CAN ANYONE HELP ME ITS URGENT :cry: :cry:

[Dogtree]

>> Temperary variable to be passed in recursive function
No.

>> temparary variable are temparary to scope of function
Yea.

>> and in recursive function we use global variable sort of things
What are you babbling about? It's possible and perfectly reasonable to use a non-static local variable in a recursive function. This function doesn't need a static variable or a global variable. Here's your current function:

list *reverse (list *head)
{
  if (head->next == NULL)
  {
    tail = head;
    return;
  }else{
    reverse (head->next);
    head->next->next = head;
    head->next = NULL;
  }
}

Here's my modification using a local temporary:

link *reverse_list(link *head)
{
  link *temp;

  if (head->next == 0) temp = head;
  else {
    temp = reverse_list(head->next);
    head->next->next = head;
    head->next = 0;
  }

  return temp;
}

The algorithm is identical, but my function is completely self-contained and works properly whereas yours would have unnecessary coupling with that global variable if you kept following the same line of thinking.

[happyshub]

Ohhh thanks .....Its finally working ..