Question

I am trying to remove an element from a vector using std::remove and std::erase.
I do not know the index, only the value. However, it doesn’t work, it probably has to do with operators for my custom struct, but I don’t know how to fix it.

The problem is this line of code:

stillAvailable.erase(remove(stillAvailable.begin(), stillAvailable.end(), previousRound[j]), stillAvailable.end());

Where stillAvailable is of type std::vector and previousRound[j] is of type Team. Team is a struct that looks like this:

struct Team
{
  int country;
  std::string name;
  int positionGP;
  int groupID;
};

I get the following error codes:

League.cc: In member function `bool League::generateSchema(int, std::vector<Team, std::allocator<Team> >)':
League.cc:131: error: no match for 'operator*' in '*temp'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h: In function `_OutputIterator std::remove_copy(_InputIterator, _InputIterator, _OutputIterator, const _Tp&) [with _InputIterator = __gnu_cxx::__normal_iterator<Team*, std::vector<Team, std::allocator<Team> > >, _OutputIterator = __gnu_cxx::__normal_iterator<Team*, std::vector<Team, std::allocator<Team> > >, _Tp = Team]':
C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:1114:   instantiated from `_ForwardIterator std::remove(_ForwardIterator, _ForwardIterator, const _Tp&) [with _ForwardIterator = __gnu_cxx::__normal_iterator<Team*, std::vector<Team, std::allocator<Team> > >, _Tp = Team]'
League.cc:145:   instantiated from here
C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:1037: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __value'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h: In function `_RandomAccessIterator std::find(_RandomAccessIterator, _RandomAccessIterator, const _Tp&, std::random_access_iterator_tag) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Team*, std::vector<Team, std::allocator<Team> > >, _Tp = Team]':
C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:314:   instantiated from `_InputIterator std::find(_InputIterator, _InputIterator, const _Tp&) [with _InputIterator = __gnu_cxx::__normal_iterator<Team*, std::vector<Team, std::allocator<Team> > >, _Tp = Team]'
C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:1112:   instantiated from `_ForwardIterator std::remove(_ForwardIterator, _ForwardIterator, const _Tp&) [with _ForwardIterator = __gnu_cxx::__normal_iterator<Team*, std::vector<Team, std::allocator<Team> > >, _Tp = Team]'

League.cc:145:   instantiated from here
C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:207: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:211: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:215: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:219: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:227: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:231: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

C:/Dev-Cpp/include/c++/3.4.2/bits/stl_algo.h:235: error: no match for 'operator==' in '(&__first)->__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Team*, _Container = std::vector<Team, std::allocator<Team> >]() == __val'

Any help would be greatly appreciated! Thanks in advance!

Answer 1

std::remove uses operator==, which is not overloaded automatically for your classes and structs. You will have to write it yourself:

bool operator==(const Team & lhs, const Team & rhs)
{
    // compare lhs and rhs in such a way that you return true if they
    // are equal, and false if they are not equal.  You can define
    // equal to mean whatever you want here.
}