STL---下一个排列

#include "iostream"
#include "algorithm"
using namespace std;


int main()
{
    int a[3] = {3, 1, 2};
    sort(a, a+3);     //从小到大排序, 如果不排序，则得不到全部排列结果
    do
    {
        for(int i=0; i<3; i++)
            cout << a[i];
        cout << endl;
    }while(next_permutation(a, a+3));   //下一个排列
    return 0;
}

#include "iostream"
#include "algorithm"
#include "set"
using namespace std;
int main()
{
    set<int> s;
    s.insert(4);
    s.insert(3);
    s.insert(2);
    s.insert(1);
    set<int>::iterator it;

    do
    {
        for(it=s.begin(); it!=s.end(); it++)
            cout << (*it) << " ";
        cout << endl;
    }while(next_permutation(s.begin(), s.end()));

    return 0;
}