Error in VS2010 with set_intersection() and set<int>
-
28-06-2021 - |
Domanda
I am trying to use the set_intersection() function. My code looks like below
set<int> IntersectionSet;
for(map<string, set<int>>::iterator it = mapArtist.begin() ; it != mapArtist.end() ; ++it)
{
for(map<string, set<int>>::iterator it2 = it ; ++it2 != mapArtist.end() ; ++it2)
{
set<int>::iterator iter = set_intersection(it->second.begin(), it->second.end(), it2->second.begin(), it2->second.end(), std::inserter(IntersectionSet, IntersectionSet.begin()));
if(IntersectionSet.size() >= 300) cout << it->first << " " << it2->first << "\n";
IntersectionSet.clear();
}
}
The issue here seemsto be with the line
set<int>::iterator iter = set_intersection(it->second.begin(), it->second.end(), it2->second.begin(), it2->second.end(), std::inserter(IntersectionSet, IntersectionSet.begin()));
which seems to be correct compared to uses in some other pages I saw on this site. I get the following error while compiling
1>c:\users\Machine\documents\visual studio 2010\projects\artists\artists\artists.cpp(109): error C2440: 'initializing' : cannot convert from 'std::insert_iterator<_Container>' to 'std::_Tree_const_iterator<_Mytree>'
1> with
1> [
1> _Container=std::set<int>
1> ]
1> and
1> [
1> _Mytree=std::_Tree_val<std::_Tset_traits<int,std::less<int>,std::allocator<int>,false>>
1> ]
1> No constructor could take the source type, or constructor overload resolution was ambiguous
1>
1>Build FAILED.
What am I missing here? Thanks.
Soluzione
The problem is here:
set<int>::iterator iter = set_intersection(/*...*/);
std::set_intersection
returns the inserter, which in your code is a std::insert_iterator
, not a std::set<int>::iterator
.
Since you don't use iter
, you don't need to do anything with the return value at all; just call std::set_intersection
.
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