Re: how to sort std::vector contains user defined struct by multiple value?

Hi, all:

I have a std::vector which contains my struct. The data in the vector
is inserted from a std::map, then I will need to sort the vector based
on some criteria and then get the sorted data out. my struct is like:

struct item
{
    int itemtypeid;
    int itemid;

};

typedef std::deque<item> ItemList;
struct order
{
     int orderid;
     int ordertypeid;
     ItemList itemdata;

};

typedef std::vector<order> VectorOrder;

I use a functor to do the sort by orderid

this is the functor:
class COrderSorter
{
public:
        bool operator()(const order& lhs, const order& rhs)
        {
                return lhs.orderid < rhs.order;
        }

};

VectorOrder m_vecOrder

std::sort(m_vecOrder.begin(), m_vecOrder.end(), COrderSorter());

NOW, I need to sort the order by the its item first by itemtypeid,
then by itemid.
for example:
orderid itemtypeid itemid
    1 2 4
    1 2 3
    1 1 5
    2 1 2

the final result I need to get:
orderid itemtypeid itemid
    2 1 2
    1 1 5
    1 2 3
    1 2 4

Is there a way to achieve this other than the plain iterate through
every order and then iterate through its item?
What the efficient, memory consideration about this?

thanks in advance
-rockdale