sorted linked list

It is usual to keep a linked list sorted. That means rather than just inserting new nodes at the head or tail of the list you insert them at the right place.
Lets build a list with your example we will add the numbers 3,4,2,6,5,1 like this.

Code:

head of list is a null pointer of type node* allocate memory for a node using new assigning pointer to head add 3 to data field add null to next field (i.e. no next node) list looks like.... 3--NULL now we need to add a new node to hold the value 4. compare 4 to head->item if less add at front. but its not so we compare to next node and there isn't one so call insert at back func. list now looks like 3--4--NULL now we compare 2 to head->item and find its less so call add at front func to end up with a new list like.... 2--3--4--NULL now we compare 6 to head->item and find its greater so we traverse the list until we find where to insert. In this case its a call to insert at back func again list now looks like 2--3--4--6--NULL now we add 5 so we compare again to head->item and follow the next pointers through the list until we compare to 6 and find its less so we insert new node just before 6 list now looks like 2--3--4--5--6--NULL adding the 1 is just a compare then add at front to get 1--2--3--4--5--6--NULL and your list is sorted as its built.

The inserts are nothing more than a bit of pointer manipulation and dynamic memory allocation.