Sorting a list of type class

[KALIDA]

I have declared a list from the STL. This is a list of the type of class. But I am unable to work out my operator:

class Node
{
public:
string label;
list<Node*> child;
bool operator< (const Node *c1)
{
 return label < c1->label;
}
Node (string text)
{
 label=text;
}
void addChild(string text)
{
 Node* newNode = new Node (text);
 child.push_front(newNode);
}
void display(int NbTab)
{
 if (!child.empty())
 {
  child.sort();
  insertTab(NbTab);
  cout<<label<<endl;
  list<Node*>::iterator it;
  for (it=child.begin(); it!=child.end(); ++it)
  {
   (*it)->display(NbTab+1);
  }
 }
 else
 {
  insertTab(NbTab);
  cout<<label<<endl;
 }
}
};
int main(void)
{
Node* level1=new Node ("Level1" );
Node* level4=new Node ("Level4" );
level1->addChild("Level20" );
level1->addChild("Level22" );
level1->addChild("Level23" );
level1->addChild("Level21" );
level1->child.front()->addChild("test2" );
level1->child.front()->addChild("test1" );
level1->child.front()->addChild("test3" );
level1->display(0);
level1->child.sort();
level1->display(0);
return 0;
}

Here is the return to the console:

Niveau1
Level20
Level22
Level23
Level21
test2
test1
test3
Level1
Level20
Level22
Level23
Level21
test2
test1
test3
Press any key to continue

I display my list, everything is OK and it is in disorder (order in which I returned). I then re-sort it but still the order remains the same. Could someone tell me what I miss? Can you help me how to sort a list that is of type class?

[!const]

How does nothing happens? It sorts according to your pointers, as you probably ask him.

A list of pointers will be sorted with the order defined on pointers, not objects points if you do not explicitly specify the comparison function to use.

[opaper]

You can call out to passing it as argument may be, its the predicate that will make the comparison as you want between nodes

bool pred( const Node *l, const Node *r )
{
return l->label < r->label;
}
// ...
level1->child.sort(pred);

Incidentally, you note that your sort is not deep, you can sort the child of a node, not the small child.

[KALIDA]

@ const: How can I specify this function to sort my list as per my requirement?

@ opaper: thank you for enlightening me, I confess that I passed but I think you've noticed

I already try the same thing, the problem is that I can not use it in my class node (in any case I failed)

[opaper]

The predicate should not be a member function of your class or it is necessary that he be declared as static member. Always see what you try and what errors do you get, it will be quicker to help.