#include<set>
//定义一个整型数据的集合
std::set<int> set;

#include<set>
int array[5]={12, 34, 10, 98, 3};
const size_t array_size=sizeof(array)/sizeof(array[0]);
std::set<int> set;
for(size_t i=0; i<array_size;++i)
{
        //把数据插入集合，数据自动排序
        set.insert(array[i]);
}

//此时已经排序了，下面依次输出
std::set<int>::const_iterator b=set.begin();
for(; b!=set.end();++b)
{
        std::cout<<*b << '\n';
}

#include<set>
int array[5]={12, 34, 10, 98, 3};
const size_t array_size=sizeof(array)/sizeof(array[0]);
//一个新的定义容器的方法
std::set<int> set(array, array+array_size);

//插入一个元素
set.insert(23);
//移除一个元素
set.erase(10);
//移除一个元素不在集合中的元素
//此时什么也不做，n作为返回值将会是0
//指明没有元素移除
size_t n=set.erase(11);

//使用迭代器，找到一个元素
std::set<int>::const_iterator result=set.find(98);

std::set<int> other;
//交换两个集合的内容
std::swap(set, other);

//清除所有的内容
other.clear()

;

#include<set>
#include<iterator>
#include<iostream>
#include <algorithm>
using namespace std;
int main()
{
    set<int> eg1;
    eg1.insert(1);
    eg1.insert(100);
    eg1.insert(5);
    eg1.insert(1); //元素1因为已经存在所以set中不会再次插入1
    eg1.insert(10);
    eg1.insert(9);
    //遍历set，可以发现元素是有序的
    set<int>::iterator set_iter=eg1.begin();
    cout<<"Set named eg1:"<<endl;
    for(;set_iter!=eg1.end();set_iter++) cout<<*set_iter<<" ";
    cout<<endl;
    //使用size()函数可以获得当前元素个数
    cout<<"Now there are "<<eg1.size()<<" elements in the set eg1"<<endl;
    if(eg1.find(200)==eg1.end())//find()函数可以查找元素是否存在
        cout<<"200 isn't in the set eg1"<<endl;

 

    set<int> eg2;
    for(int i=6;i<15;i++)
        eg2.insert(i);
    cout<<"Set named eg2:"<<endl;
    for(set_iter=eg2.begin(); set_iter!=eg2.end(); set_iter++)
        cout<<*set_iter<<" ";
    cout<<endl;

    //获得两个set的并
    set<int> eg3;
    cout<<"Union(两个set的并集):";
    set_union(eg1.begin(),
              eg1.end(),
              eg2.begin(),
              eg2.end(),
              insert_iterator<set<int> >(eg3, eg3.begin())
              );//注意第五个参数的形式
    copy(eg3.begin(), eg3.end(), ostream_iterator<int>(cout," "));
    cout<<endl;

    //获得两个set的交，注意进行集合操作之前接收结果的set要调用clear()函数清空一下
    eg3.clear();
    set_intersection(eg1.begin(),
                     eg1.end(),
                     eg2.begin(),
                     eg2.end(),
                     insert_iterator<set<int> >(eg3,eg3.begin())
                     );
    cout<<"Intersection:";
    copy(eg3.begin(),eg3.end(),ostream_iterator<int>(cout," "));
    cout<<endl;

    //获得两个set的差
    eg3.clear();
    set_difference(eg1.begin(),
        eg1.end(),eg2.begin(),
        eg2.end(),
        insert_iterator<set<int> >(eg3,eg3.begin())
        );
    cout<<"Difference:";
    copy(eg3.begin(),eg3.end(),ostream_iterator<int>(cout," "));
    cout<<endl;

    //获得两个set的对称差，也就是假设两个集合分别为A和B那么对称差为AUB-A∩B
    eg3.clear();
    set_symmetric_difference(eg1.begin(),eg1.end(),eg2.begin(),eg2.end(),insert_iterator<set<int> >(eg3,eg3.begin()));
    copy(eg3.begin(),eg3.end(),ostream_iterator<int>(cout," "));
    cout<<endl;

    return 0;
}

 

下面给出一个关键字类型为char*的示例代码

#include<iostream>
#include<iterator>
#include<set>
using namespace std;
struct ltstr
{
bool operator() (const char* s1, const char* s2) const
{
    return strcmp(s1, s2) < 0;
}
};

int main()
{
const int N = 6;
const char* a[N] = {"isomer", "ephemeral", "prosaic",
    "nugatory", "artichoke", "serif"};
const char* b[N] = {"flat", "this", "artichoke",
    "frigate", "prosaic", "isomer"};

set<const char*,ltstr> A(a, a + N);
set<const char*,ltstr> B(b, b + N);
set<const char*,ltstr> C;

cout << "Set A: ";
//copy(A.begin(), A.end(), ostream_iterator<const char*>(cout, " "));
set<const char*,ltstr>::iterator itr;
for(itr=A.begin();itr!=A.end();itr++) cout<<*itr<<" ";
cout << endl;
cout << "Set B: ";
copy(B.begin(), B.end(), ostream_iterator<const char*>(cout, " "));   
cout << endl;

cout << "Union: ";
set_union(A.begin(), A.end(), B.begin(), B.end(),
     ostream_iterator<const char*>(cout, " "),
     ltstr());   
cout << endl;

cout << "Intersection: ";
set_intersection(A.begin(), A.end(), B.begin(),B.end(),ostream_iterator<const char*>(cout," "),ltstr());
cout<<endl;
set_difference(A.begin(), A.end(), B.begin(), B.end(),inserter(C, C.begin()),ltstr());
cout << "Set C (difference of A and B): ";
copy(C.begin(), C.end(), ostream_iterator<const char*>(cout, " "));
cout <<endl;
return 0;
}

其中的ltstr也可以这样定义
class ltstr
{
         public:
         bool operator() (const char* s1,const char*s2)const
         {
                 return strcmp(s1,s2)<0;
         }
};

更加通用的应用方式那就是数据类型也是由用户自定义的类来替代，比较的函数自定义，甚至可以加上二级比较，比如首先按照总分数排序，对于分数相同的按照id排序，下面是示例代码

#include<set>
#include<iostream>
using namespace std;
struct
{
                 int id;
                 int score;
                 string name;
};
struct compare
{
         bool operator()(const Entity& e1,const Entity& e2)const    {
                 if(e1.score<e2.score) return true;
                 else
                         if(e1.score==e2.score)
                                 if(e1.id<e2.id) return true;

                 return false;
         }
};

int main()
{
         set<Entity,compare>s_test;
         Entity a,b,c;
         a.id=123;a.score=90;a.name="bill";
         b.id=121;b.score=85;b.name="mary";
         c.id=130;c.score=85;c.name="jerry";
         s_test.insert(a);s_test.insert(b);s_test.insert(c);
         set<Entity,compare>::iterator itr;
         cout<<"Score List(ordered by score):\n";
         for(itr=s_test.begin();itr!=s_test.end();itr++)
                 cout<<itr->id<<"---"<<itr->name<<"---"<<itr->score<<endl;
         return 0;
}