STL set container

#include <set>
#include <string>
#include<iostream>
using namespace std;
int main()
{
    set<string> db;
    db.insert(string("abs"));
    db.insert(string("abd"));
    db.insert(string("abe"));
    db.insert(string("abc"));
    db.insert(string("aba"));

    // Delete .
    db.erase(string("abe"));
    //db.erase("abe");

    // Iterator output
    set<string>::iterator ite = db.begin();
    for ( ite; ite !=db.end(); ite++)
    {
        cout << *ite<<endl;
    }

    system("pause");
    return 0;
}

set:

1、 Keyword save ： Sort by actual value , Find by actual value ;

                            characteristic ：ａ、 Efficient access , contrast map：

                                             1、 The data structure is a red black tree ;

                                             2、map It is a sub key value pair ,set The key value is the actual value , The actual value is the key value .

                                       b、 Key values cannot be repeated .

2、 Red and black trees （ Balance   Sort binary trees ）：x=log2^N:

                                                                      a、N Is the total amount of data .

                                                                      b、x Is the number of lookups ,2^x>=N.

3、 Key value cannot be changed , The actual value can be changed . But generally, modifying the actual value means that modifying the key value will change the whole structure , Generally, modification is not advocated .

4、 No capacity ; Get the number of elements ,size(), Size ; Get whether an element exists , Or judge whether an element exists , count(const key&_key); Determine whether it is empty empty(), Empty return 1, Not empty return 0; iterator , It can cycle 、 You can also add it yourself ++, But not +2.