Insert nodes into a linked list in a sorted fashion

The solution is to iterate down the list looking for the correct place to insert the new node. That could be the end of the list, or a point just before a node which is larger than the new node.

Note that we assume the memory for the new node has already been allocated and a pointer to that memory is being passed to this function.



// Special case code for the head end
void linkedListInsertSorted(struct node** headReference, struct node* newNode) 
{
  // Special case for the head end
  if (*headReference == NULL || (*headReference)->data >= newNode->data)
  {
     newNode->next = *headReference;
     *headReference = newNode;
  }
  else
  {
     // Locate the node before which the insertion is to happen!
     struct node* current = *headReference;
     while (current->next!=NULL && current->next->data < newNode->data)
     {
        current = current->next;
     }
     newNode->next = current->next;
     current->next = newNode;
   }
}