c++ - Using iterators on maps -

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map<double, latlon> closestpoi;  map<double, latlon> ::iterator iterpoi = closestpoi.begin();

i made tree keyed distance between 2 points. need find 3 points in tree smallest (3 smallest distances). declared iterator , initialized point @ root (i'm not sure if necessary didn't solve problem). tried using advance(iterpoi, 1) increment iterator didn't work either. how can find these 3 points , access values?

note: yes know 3 nodes want root , kids (since have smallest distances)

usually use for() loop iterate map:

for(map<double, latlon> ::iterator iterpoi = closestpoi.begin();     iterpoi != closestpoi.end();     ++iterpoi) {     // access iterator's key: iterpoi->first ...     // access iterator's value: iterpoi->second ... }

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