C++ set增刪改查遍歷

int main()
{
    set<int> test;
    //插入
    test.insert(2);
    test.insert(1);
    test.insert(4);
    test.insert(5);
    test.insert(3);
    //遍歷
    for (auto i : test)
        cout << i << endl;
    cout << endl;
    auto iter = test.rbegin();//最大的N個數
    for (int i = 0; i < 3;i++)
        cout << *iter++ << endl;//雙向迭代器不支持隨機訪問
    //刪除    
    test.erase(4);//特定元素
    auto it = test.begin();//最小的N個數
    for (int i = 0; i < 2;i++)
        it=test.erase(it);
    //查找
    if (test.find(5) != test.end())
        cout << "find it" << endl;

    return 0;
}