Re: converting between STL data structures

"Igor Tandetnik" <>
Fri, 29 Sep 2006 15:02:48 -0400
PaulH <> wrote:

I have an STL structure that loooks like this:
std::map<int /*dataC*/, std::map<DWORD /*dataB*/, DWORD /*dataA*/> >
That's just the easiest way I found to save the data based on the way
it's entered.

But, when I want to retrieve the data, I need a structure more like
std::map<DWORD /*dataB*/, std::map<int /*dataC*/, DWORD /*dataA*/> >

is there any way of converting from 'oldRes' to 'newRes'?

typedef std::map<DWORD, DWORD> OldMapInner;
typedef std::map<int, OldMapInner> OldMap;
typedef std::map<int, DWORD> NewMapInner;
typedef std::map<DWORD, NewMapInner> NewMap;

OldMap oldRes;
NewMap newRes;

for (OldMap::iterator om = oldRes.begin(); om != oldRes.end(); ++om) {
    int dataC = om->first;
    OldMapInner& inner = om->second;
    for (OldMapInner::iterator omi = inner.begin(); omi != inner.end();
++omi) {
        DWORD dataB = omi->first;
        DWORD dataA = omi->second;

        newRes[dataB][dataC] = dataA;

With best wishes,
    Igor Tandetnik

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