1、构造函数

#include <iostream>
#include <set>

int main ()
{
    int ary[] = { 5,3,7,5,2,3,7,5,5,4 };
    set<int> s1;
    set<int, greater<int> > s2;
    for ( int i=0; i<sizeof(ary)/sizeof(int); i++ )
    {
        s1.insert(ary[i]);
        s2.insert(ary[i]);
    }
    set<int>::iterator It = s1.begin();
    cout << "s1 : ";    
    while ( It != s1.end() )
        cout << *(It++) << " ";
    cout << endl;
    It = s2.begin();
    cout << "s2 : ";    
    while ( It != s2.end() )
        cout << *(It++) << " ";
    cout << endl;
    // 第二种形式的构造
    set<int> s3(ary,ary+3);
    It = s3.begin();
    cout << "s3 : ";    
    while ( It != s3.end() )
        cout << *(It++) << " ";
    cout << endl;
    //拷贝构造
    set<int, less > s4(s1);
    It = s4.begin();
    cout << "s4 : ";
    while ( It != s4.end() )
    cout << *(It++) << " ";
    cout << endl;

    return 0;
}
运行结果:
// s1 : 2 3 4 5 7
// s2 : 7 5 4 3 2
// s3 : 3 5 7
// s4 : 2 3 4 5 7

2、begin——返回容器头

#include <iostream>
#include <set>
using namespace std;

int main ()   
{
     int ary[] = {1,2,3,2,4,5,7,2,6,8};
     set<int> s(ary,ary+10); 

     copy(s.begin(),s.end(),
             ostream_iterator<int>(cout," ")); 

     return 0;
}
运行结果: 
// 1 2 3 4 5 6 7 8

3、clear——容器就像一个盒子，clear便是拿走盒子里面的东西

#include <iostream>
#include <set>
using namespace std;

void print (set<int, less<int> >& s)
{
    set<int, less<int> >::iterator It;
    for ( It = s.begin(); It != s.end(); It++ )
        cout << *It << " ";
    cout << endl;
}
//--------------------------------------------
int main () 
{
     int ary[] = {1,2,3,2,3,4,8,2,5,6};
     set<int, less<int> > s; 

     s.insert(ary,ary+10);
     print(s); 

     s.clear();  
     cout << "Size of set s = " << s.size() << endl;
     print(s); 

     return 0;
}
运行结果:
// 1 2 3 4 5 6 8 
// Size of set s = 0

4、count——返回容器中指定元素的个数

#include <iostream>
#include <set>
using namespace std; 

void print (set<int, less<int> >& s)  
{
    set<int, less<int> >::iterator It;
    for ( It = s.begin(); It != s.end(); It++ )
        cout << *It << " ";
    cout << endl;
}
//--------------------------------------------
int main () 
{
     int ary[] = {1,2,3,2,3,4,8,2,5,6};
     set<int, less<int> > s; 

     s.insert(ary,ary+10);  
     print(s); 

     cout << "count of '2' (0 or 1) is ";
     int n = s.count(2); 

     cout << n << endl; 
返回first和last之间等于val的元素区间. 此函数假定first和last区间内的元素可以使用<操作符或者指定的comp执行比较操作.
     return 0;
}
运行结果:
// 1 2 3 4 5 6 8 
// count of '2' (0 or 1) is 1

5、empty——判断容器内元素是否为空

#include <iostream>
#include <set>
using namespace std; 

void print (set<int, less<int> >& s)
{
    set<int, less<int> >::iterator It; 
    for ( It = s.begin(); It != s.end(); It++ )
        cout << *It << " ";
    cout << endl;
}
//--------------------------------------------
int main () 
{
     int ary[] = {1,2,3,2,3,4,8,2,5,6};
     set<int, less<int> > s;

     s.insert(ary,ary+10);
     print(s);

     cout << "set is " << ((s.empty()) ? "" : "not ")
           << "empty" << endl; 

     s.clear(); 

     cout << "set is " << ((s.empty()) ? "" : "not ")
           << "empty" << endl; 

     return 0;
}
运行结果:
// 1 2 3 4 5 6 8 
// set is not empty
// set is empty

6、end——容器迭代器最后一个元素的下一个迭代

#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std; 

template <class T>
class Member
{
    public:
        Member(T l, T f) : last(l), first(f) {}
        void print() const // const !!!
        {
            cout.setf(ios::left);
            cout << setw(15) << first.c_str()
                 << last << endl;
        }
    private:
        T first, last;
    // const !!!
    friend bool operator < (const Member& m1, const Member& m2)
    {
        return (m1.last < m2.last) ? true : false;
    }
    friend bool operator == (const Member& m1, const Member& m2)
    {
        return (m1.last == m2.last) ? true : false;
    }
};
//===============================================
int main () 
{
    typedef Member<string> M;
    typedef set<M, less<M> > S;
    M m("Frost","Robert");

    S s; 

    s.insert(m);
    s.insert(M("Smith","John"));  
    s.insert(M("Amstrong","Bill"));
    s.insert(M("Bain","Linda")); 

    S::iterator It = s.begin();
    while ( It != s.end() )
        (It++)->print(); 

    return 0;  
}
运行结果:  
// Bill           Amstrong 
// Linda          Bain
// Robert         Frost
// John           Smith

<7、equal_range——返回first和last之间等于指定元素的区间. 此函数假定first和last区间内的元素可以使用<操作符或者指定的comp执行比较操作.>

#include <iostream>
#include <set>
using namespace std; 

int main ()  
{
    set<int> c; 

    c.insert(1);  
    c.insert(2);
    c.insert(4);
    c.insert(10);
    c.insert(11); 

    cout << "lower_bound(3): " 
        << *c.lower_bound(3) << endl;
    cout << "upper_bound(3): " 
        << *c.upper_bound(3) << endl;
    cout << "equal_range(3): " 
        << *c.equal_range(3).first << " "
         << *c.equal_range(3).second << endl;
    cout << endl;
    cout << "lower_bound(5): " 
        << *c.lower_bound(5) << endl;
    cout << "upper_bound(5): " 
        << *c.upper_bound(5) << endl;
    cout << "equal_range(5): " 
        << *c.equal_range(5).first << " "
         << *c.equal_range(5).second << endl;
cin.get();  
}
运行结果:
// lower_bound(3): 4
// upper_bound(3): 4
// equal_range(3): 4 4
//
// lower_bound(5): 10
// upper_bound(5): 10
// equal_range(5): 10 10 

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