Thread: std:: list liste.sort ();

I have declared a list from the STL. This is a list of the type of class.

===> List <NomDeClasse> list;

I do a lot of this list thanks to the Sort method provided in the class list of c + + builder.

How can the list be sorted according to a field (string) being in my class.

I was told it was overloading the operator <but I do not see how!

Thank you for helping me.

You can define:

Code:

1.	struct (MyGreater
2.	bool operator () (const ClassName & c1, const ClassName & c2)
3.	(
4.	return c1.champ> c2.champ;
5.	);6.	)

After that

Code:

1.	liste.sort (MyGreater ());

And to make it in reverse order
MyGreater you replace the inverse function

A +

There is no method std:: list:: sort in STL all confused.

used std:: sort

you can not use sort of algorithm on lists, but you probably ought to know that.

Yes I misspoke and that's not true that I have eyes in front of the hole after 7 games in a row War3.

Hi, dsl to determine the subject but I have a very similar problem. Unable to work out my operator:

Code:

1.	class Node
2.	(
3.	public:
4.	string libel;
5.	list <Noeud *> son;
6.	
7.	bool Node:: operator <(const Node & n) / / returns true if the libel of me meme is located before the wording of N
8.	(
9.	return libel <N.libelle;
10.	)11.	...

when I use spell on my list <Noeud *> it nothing happens.

Could someone tell me what I miss?
thank you

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

Nothing is happening, because it is not clear.

I have a list <Noeud *> I filled (with libel in a disorder Alphabetically). I display my list -> everything is OK it is in disorder (order in which I returned).

I then re-released poster -> order is always the same of it or nothing happens.

Because the AC is running out of useful info to really see the problem.

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.

Code:

1.	class Node
2.	(
3.	public:
4.	
5.	string libel;
6.	list <Noeud *> son;
7.	
8.	bool operator <(const Node * c1)
9.	(
10.	return libel <c1-> libel;
11.	)
12.	
13.	Node (string text)
14.	(
15.	libel = text;
16.	)
17.	
18.	ajouterFils void (string text)
19.	(
20.	* NouveauNoeud node = new Node (text);
21.	fils.push_front (nouveauNoeud);
22.	)
23.	void display (int NbTab)
24.	(
25.	if (! fils.empty ())
26.	(
27.	fils.sort ();
28.	insererTab (NbTab);
29.	court <<libel <<endl;
30.	<Noeud*> list:: iterator it;
31.	for (it = fils.begin (); it! fils.end = () + + it)
32.	(
33.	(* it) -> display (NbTab 1);
34.	)
35.	)
36.	else
37.	(
38.	insererTab (NbTab);
39.	court <<libel <<endl;
40.	)
41.	)
42.	
43.	);
44.	
45.	
46.	
47.	int main (void)
48.	(
49.	* Level 1 node = new Node ( "Level1");
50.	* Level 4 Node = new Node ( "Level 4");
51.	
52.	level1-> ajouterFils ( "Niveau20");
53.	level1-> ajouterFils ( "Niveau22");
54.	level1-> ajouterFils ( "Niveau23");
55.	level1-> ajouterFils ( "Niveau21");
56.	
57.	level1-> fils.front () -> ajouterFils ( "test2");
58.	level1-> fils.front () -> ajouterFils ( "test1");
59.	level1-> fils.front () -> ajouterFils ( "test3");
60.	
61.	level1-> display (0);
62.	level1-> fils.sort ();
63.	level1-> display (0);
64.	
65.	return 0;66.	)

Here is the return to the console:

Code:

1.	Level1
2.	Niveau20
3.	Niveau22
4.	Niveau23
5.	Niveau21
6.	test2
7.	test1
8.	test3
9.	Level1
10.	Niveau20
11.	Niveau22
12.	Niveau23
13.	Niveau21
14.	test2
15.	test1
16.	test3
17.	Press any key to continue

you can call out to passing it as argument a predicate is the predicate that will make the comparison as you want between nodes

Edit, just to chew you work if my explanation is not clear enough:

Code:

1.	bool pred (const Node * l, const Node * r)
2.	(
3.	return l-> label <r-> libel;
4.	)
5.	/ / ...
6.	level1-> fils.sort (pred);

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

Edit: const