C + + set basic operations

1. Element insert: Insert ()
2. Middle sequence traversal: vector-like traversal (with iterators)
3. Reverse traversal: Use the reverse iterator reverse_iterator.
Cases:
Set<int> s;
......
Set<int>::reverse_iterator RIT;
For (Rit=s.rbegin (); Rit!=s.rend (); rit++)
4. Element removal: As with insertions, it can be efficiently removed and automatically adjusted to make the red-black tree balanced.
Set<int> s;
S.erase (2); Delete an element with a key value of 2
S.clear ();
5. Element search: Find (), if found, returns the position of the key-value iterator, otherwise, returns a position after the last element.
Set<int> s;
Set<int>::iterator it;
It=s.find (5); Find an element with a key value of 5
if (It!=s.end ())//Found
cout<<*it<<endl;
else//not found
cout<< "not Found";
6. Custom comparison functions
(1) The element is not a struct:
Cases:
Custom comparison function MyComp, overloaded "()" operator
struct MYCOMP
{
BOOL Operator () (const your_type &a,const your_type &b)
[
Return a.data-b.data>0;
}
}
set<int,mycomp>s;
......
Set<int,mycomp>::iterator it;
(2) If the element is a struct, the comparison function can be written directly in the structure body.
Cases:
struct INFO
{
String name;
Float score;
Overloaded "<" operator, custom collation
BOOL operator < (const Info &a) const
{
Press score to arrange from large to small
Return a.score<score;
}
}
Set<info> s;
......
Set<info>::iterator it;

Set_intersection (S.begin (), S.end (), S2.begin (), S2.end (), Inserter (Si, Si.begin ())); //Intersection
Set_union (S.begin (), S.end (), S2.begin (), S2.end (), Inserter (Su, Su.begin ())); //and set
Set_difference (S.begin (), S.end (), S2.begin (), S2.end (), Inserter (Sd, Sd.begin ())); //Difference set
Set_symmetric_difference (S.begin (), S.end (), S2.begin (), S2.end (), Inserter (SSD, Ssd.begin ())); //Symmetric difference set

C + + set basic operations