stl container with 2 keys

Hello all,

I need a container which can handle 2 keys. Actually I need the sequence is sorted by primary key(a date time) and then second key(a businessId). Can any body help me on this?

Thanks in advance.

You can use pretty much any container you want, you just need
to specify a sorting function ob ject that does what you want.
Here is a sample using vector and set ...

Code:

---

#include <vector>
#include <algorithm>
#include <iostream>
#include <set>

struct S
{
    S() {}
    S(int d , int i) : date(d) , id(i) {}
    int date;
    int id;
};

struct SortByDateID
{
    bool operator () (const S & lhs , const S & rhs) const
    {
        // sort by primary key first (date)

        if ( lhs.date < rhs.date ) return true;
        if ( lhs.date > rhs.date ) return false;

        // here the dates are equal , sort by secondary key (id)

        return lhs.id < rhs.id;
    }
};

using namespace std;

int main()
{
    vector<S> v;

    v.push_back( S(1,1) );
    v.push_back( S(2,3) );
    v.push_back( S(5,1) );
    v.push_back( S(2,1) );
    v.push_back( S(2,8) );

    sort( v.begin() , v.end() , SortByDateID() );

    //print sorted vector

    for (int i=0; i<v.size(); ++i)
    {
        cout << v[i].date << " : " << v[i].id << "\n";
    }

    cout << "\n\n\n";

    set<S,SortByDateID> s;
   
    s.insert( S(1,1) );
    s.insert( S(2,3) );
    s.insert( S(5,1) );
    s.insert( S(2,1) );
    s.insert( S(2,8) );

    set<S,SortByDateID>::iterator it = s.begin();

    while (it != s.end())
    {
        cout << it->date << " : " << it->id << "\n";
        ++it;
    }

    return 0;
}

---

Thanks Philip.
Let me extend my requirement. I need an automatic sortable container that can sort by the primary key; I need another mechanism to sort the elements by second key. I need these can be done automatically when I insert an element into the container.
What I am trying is to do is using a multimap to control a sequence of pointer pair. (*it)->first is a pointer to a structure that contains a date and an ID. I can provide a Less<key> function to the container like this:
class MyLess : public binary_function<CKeyStru *, CMyValue *, bool>
{
public:
bool operator()(const CKeyStru * p1, const CKeyStru * p2) const
{
return (_tcscmp(p1->m_bstrId, p2->m_bstrId) < 0);
}
};

Now the elements are sorted by ID in the container. I need it can sorted by second key which is date time. I know that multiset can't do this but I just use this as an example. During the retrieving I can use a loop but I don't want to use a loop.

Any idea is apprecated.