Re: [Dev-C++] Linked List and Pointers

[Michal M. <mol...@se...>]

Sorry for the formatting

Dne 2.5.2011 4:33, Jordan Burnam napsal(a):
> void linklist::append(int num)
> {
> node *newNode = new node;
> node *nextNode = new node;
> if (p == NULL)
> {
> p = newNode;
> p ->data = num;
> p->link = NULL;
> }
>
> else

{ // missing

> newNode = new node;
> node * n = p;
> while(n -> link){n = n -> link;}
> n-> link = newNode;
>
> newNode -> data = num;
> newNode -> link = NULL;

} // missing

> }

> void linklist::next( int c, int num)
> {
> node *lastNode;

you never read value of lastNode so can get rid of it

> node *currNode;
> node *nextNode;
>
> currNode = p;
> lastNode = currNode;
> nextNode = currNode -> link;

the line above will fail if the list is empty, you should check that 
situation

>
> while(c != 0)
> {
> lastNode = currNode;
> currNode = currNode -> link;
> nextNode = currNode -> link;
> c--;

OK, but you should check if you are still inside the list
if (currNode == NULL) {
	cerr << "linklist::next: outside the list" << endl;
	return;
}

> }



>
> node *newNode;
> newNode = new node;
> newNode -> data = num;
>
> currNode -> link = newNode;
> newNode -> link = nextNode;
>
> }

  void linklist::del( int num )
  {
  node * lastNode;
  node * currNode;

  currNode = p;
  lastNode = NULL;


  while(currNode != NULL)
  {
     if(currNode -> data == num)
     {

        if (lastNode) {
	   lastNode->link = currNode->link;
            delete currNode;	
        }
        else { // it was the first node in the list
	  node* n = p;
           p = p->link;
           delete n;
        }

        return;

     }
     else
   { // should be here although it accidentally works even without them

          lastNode = currNode;
          currNode = currNode -> link;
   } // should be here although it accidentally works even without them
  } // if
  } // while

  cout << "Item not found" << endl;
  }

  > void linklist::display()
should be OK

int linklist:: count ()
{
int count =0;
node *a_node;
a_node = p;

while(a_node != NULL)
{
count++;
a_node = a_node -> link;
}

return count;}