Accessing elements in maps of maps with vectors of shared pointers - c++

Question

I have a somewhat unique situation that I can't quite get working.
I've followed a lot of examples of using maps of maps but the vector of shared pointers seems to throw me off a bit.
Suppose I have the following:
typedef boost::shared_ptr<RecCounts> RecCountsPtr;
typedef std::vector<RecCountsPtr> RecCountsPtrVec;
typedef std::map<std::string, RecCountsPtrVec> InnerActivityMap;
typedef std::map< std::string, InnerActivityMap > ActivityMap;
Where RecCounts is a simple structure.
Now, I think I've figured out how to populate my ActivityMap properly.
RecCountsPtr recCountsPtr(new RecCounts());
config.actType = "M";
config.mapDate = "2010/07";
recCountsPtr->iHousehold = "50";
recCountsPtr->iZero = "150";
config.actMap[config.actType][config.mapDate].push_back(recCountsPtr);
Yes? I don't get any compile/runtime errors for this...but since I haven't figured out how to access all the different elements of the map I can't confirm this!
This is the config structure:
struct Config
{
std::string actType;
std::string mapDate;
// Map
ActivityMap actMap;
InnerActivityMap innerActMap;
//Iterator
ActivityMap::iterator actMapIter;
InnerActivityMap::iterator innerActMapIter;
};
Now, suppose I want to access each element of the ActivityMap. How would I get the following elements?
The outer map Key?
for (config.actMapIter= config.actMap.begin();
config.actMapIter != config.actMap.end();
++config.actMapIter)
{
std::cout << "Outer Key = "
<< (*config.actMapIter).first << std::endl;
}
This seemed to do the trick.
The inner map Key?
I can't figure this out.
The inner map vector elements?
I can do it like this if I know the two keys:
config.actMap[config.actType][config.mapDate][0]->iHouehold
config.actMap[config.actType][config.mapDate][0]->iZero
...but can't seem to figure out how to iterate through them. :(
This is what I've done to try and iterate through all elements.
for (config.actMapIter= config.actMap.begin();
config.actMapIter != config.actMap.end();
++config.actMapIter)
{
std::cout << "Outer Key = " << (*config.actMapIter).first << std::endl;
for (config.innerActMapIter = config.innerActMap.begin();
config.innerActMapIter != config.innerActMap.end();
++config.innerActMapIter)
{
std::cout << "Inner Key = "
<< (*config.innerActMapIter).first << std::endl;
for (size_t i = 0;
i < config.actMap[(*config.actMapIter).first]
[(*config.innerActMapIter).first].size();
++i)
{
std::cout << "iHousehold = "
<< config.actMap[(*config.actMapIter).first]
[(*config.innerActMapIter).first]
[i]->iHousehold << std::endl;
std::cout << "iZero = "
<< config.actMap[(*config.actMapIter).first]
[(*config.innerActMapIter).first]
[i]->iZero << std::endl;
}
}
}
I don't get any errors but I only get the outer key print to the screen:
Outer Key = M
I suspect something is amiss with my inner iterator...in that it's not associated the ActivityMap. Even if I am correct I don't know how to make such an association.
Any suggestions?
ANSWER (thanks to crashmstr):
Here is a verbose version of the answer suggested by crashmstr.
for (config.actMapIter= config.actMap.begin();
config.actMapIter != config.actMap.end();
++config.actMapIter)
{
std::cout << "Outer Key = " << (*config.actMapIter).first << std::endl;
InnerActivityMap innerActMap = (*config.actMapIter).second;
InnerActivityMap::iterator innerActMapIter;
for (innerActMapIter = innerActMap.begin();
innerActMapIter != innerActMap.end();
++innerActMapIter)
{
std::cout << "Inner Key = " << (*innerActMapIter).first << std::endl;
for (size_t i = 0;
i < config.actMap[(*config.actMapIter).first][(*innerActMapIter).first].size();
++i)
{
std::cout << "iHousehold = "
<< config.actMap[(*config.actMapIter).first]
[(*innerActMapIter).first]
[i]->iHousehold << std::endl;
std::cout << "iZero = "
<< config.actMap[(*config.actMapIter).first]
[(*innerActMapIter).first]
[i]->iZero << std::endl;
}
}
}
I get the following printed to the screen:
Outer Key = M
Inner Key = 2010/07
iHousehold = 50
iZero = 150

Answer 1

When iterating over a map, .first is the "key", and .second is the data that belongs to that key.
So in your case:
for (config.actMapIter= config.actMap.begin();
config.actMapIter != config.actMap.end();
++config.actMapIter)
{
std::cout << "Outer Key = " << (*config.actMapIter).first << std::endl;
//(*config.actMapIter).second is a std::map<std::string, RecCountsPtrVec>
//create a new for loop to iterate over .second
}