STL---set和multiset

#include <iostream>
#include <set>
using namespace std;
int main()
{
    set<int>set1;
    for(int i=9; i>0; i--)
        set1.insert(i);  //有序插入
    set1.erase(3);
    for(set<int>::iterator p=set1.begin(); p!=set1.end(); ++p)
        cout<<*p<<"";
    cout<<endl;
    if(set1.insert(3).second)
        //把3插入到set1中
        //插入成功则set1.insert(3).second返回1，否则返回0
        //此例中，set不能插入重复元素集中已经有3这个元素了，所以插入将失败
        cout<<"set insert success";
    else
        cout<<"set insert failed";
    cout<<endl;
    for(set<int>::iterator p=set1.begin(); p!=set1.end(); ++p)
        cout<<*p<<"";
    cout<<endl;
    int a[] = {4, 1, 1, 1, 1, 1, 0, 5, 1, 0};
    multiset<int> A;
    A.insert(set1.begin(),set1.end());
    for(set<int>::iterator p=A.begin(); p!=A.end(); ++p)
        cout<<*p<<"";
    cout<<endl; 
    A.insert(a,a+10);
    for(set<int>::iterator p=A.begin(); p!=A.end(); ++p)
        cout<<*p<<"";
    cout<<endl;
    return 0;
}