Here's the definition of my class:
class F1Team {
private:
string name;
string racer1;
string racer2;
protected:
int titles;
public:
F1Team(string tnm) {
name = tnm;
titles = 0;
}
void set_racer1(string r1) {
racer1 = r1;
}
void set_racer2(string r2) {
racer2 = r2;
}
void display() {
cout<< name<< endl;
}
};
I want to store class objects mapping to an int (i.e., <int, [class]>)
Here's my code to implement it:
int main() {
map<int, F1Team> mp;
for (int i=0; i<3; ++i) {
F1Team t {"Mercedes"};
mp.insert(pair<int , F1Team>(i, t));
}
for (auto itr = mp.begin(); itr != mp.end(); ++itr) {
(*itr).second.display();
}
mp[1].display();
return 0;
}
The code throws compilation error when I try to access the object by key.
Error:
In file included from /usr/include/c++/11/bits/stl_map.h:63,
from /usr/include/c++/11/map:61,
from test.cpp:3:
/usr/include/c++/11/tuple: In instantiation of ‘std::pair<_T1, _T2>::pair(std::tuple<_Args1 ...>&, std::tuple<_Args2 ...>&, std::_Index_tuple<_Indexes1 ...>, std::_Index_tuple<_Indexes2 ...>) [with _Args1 = {int&&}; long unsigned int ..._Indexes1 = {0}; _Args2 = {}; long unsigned int ..._Indexes2 = {}; _T1 = const int; _T2 = F1Team]’:
/usr/include/c++/11/tuple:1813:63: required from ‘std::pair<_T1, _T2>::pair(std::piecewise_construct_t, std::tuple<_Args1 ...>, std::tuple<_Args2 ...>) [with _Args1 = {int&&}; _Args2 = {}; _T1 = const int; _T2 = F1Team]’
/usr/include/c++/11/ext/new_allocator.h:162:4: required from ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = std::pair<const int, F1Team>; _Args = {const std::piecewise_construct_t&, std::tuple<int&&>, std::tuple<>}; _Tp = std::_Rb_tree_node<std::pair<const int, F1Team> >]’
/usr/include/c++/11/bits/alloc_traits.h:516:17: required from ‘static void std::allocator_traits<std::allocator<_CharT> >::construct(std::allocator_traits<std::allocator<_CharT> >::allocator_type&, _Up*, _Args&& ...) [with _Up = std::pair<const int, F1Team>; _Args = {const std::piecewise_construct_t&, std::tuple<int&&>, std::tuple<>}; _Tp = std::_Rb_tree_node<std::pair<const int, F1Team> >; std::allocator_traits<std::allocator<_CharT> >::allocator_type = std::allocator<std::_Rb_tree_node<std::pair<const int, F1Team> > >]’
/usr/include/c++/11/bits/stl_tree.h:595:32: required from ‘void std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_construct_node(std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Link_type, _Args&& ...) [with _Args = {const std::piecewise_construct_t&, std::tuple<int&&>, std::tuple<>}; _Key = int; _Val = std::pair<const int, F1Team>; _KeyOfValue = std::_Select1st<std::pair<const int, F1Team> >; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, F1Team> >; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Link_type = std::_Rb_tree_node<std::pair<const int, F1Team> >*]’
/usr/include/c++/11/bits/stl_tree.h:612:21: required from ‘std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(_Args&& ...) [with _Args = {const std::piecewise_construct_t&, std::tuple<int&&>, std::tuple<>}; _Key = int; _Val = std::pair<const int, F1Team>; _KeyOfValue = std::_Select1st<std::pair<const int, F1Team> >; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, F1Team> >; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Link_type = std::_Rb_tree_node<std::pair<const int, F1Team> >*]’
/usr/include/c++/11/bits/stl_tree.h:2431:33: required from ‘std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_emplace_hint_unique(std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::const_iterator, _Args&& ...) [with _Args = {const std::piecewise_construct_t&, std::tuple<int&&>, std::tuple<>}; _Key = int; _Val = std::pair<const int, F1Team>; _KeyOfValue = std::_Select1st<std::pair<const int, F1Team> >; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, F1Team> >; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator = std::_Rb_tree<int, std::pair<const int, F1Team>, std::_Select1st<std::pair<const int, F1Team> >, std::less<int>, std::allocator<std::pair<const int, F1Team> > >::iterator; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::const_iterator = std::_Rb_tree<int, std::pair<const int, F1Team>, std::_Select1st<std::pair<const int, F1Team> >, std::less<int>, std::allocator<std::pair<const int, F1Team> > >::const_iterator]’
/usr/include/c++/11/bits/stl_map.h:520:37: required from ‘std::map<_Key, _Tp, _Compare, _Alloc>::mapped_type& std::map<_Key, _Tp, _Compare, _Alloc>::operator[](std::map<_Key, _Tp, _Compare, _Alloc>::key_type&&) [with _Key = int; _Tp = F1Team; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, F1Team> >; std::map<_Key, _Tp, _Compare, _Alloc>::mapped_type = F1Team; std::map<_Key, _Tp, _Compare, _Alloc>::key_type = int]’
test.cpp:45:9: required from here
/usr/include/c++/11/tuple:1824:9: error: no matching function for call to ‘F1Team::F1Team()’
1824 | second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test.cpp:17:9: note: candidate: ‘F1Team::F1Team(std::string)’
17 | F1Team(string tnm) {
| ^~~~~~
test.cpp:17:9: note: candidate expects 1 argument, 0 provided
test.cpp:7:7: note: candidate: ‘F1Team::F1Team(const F1Team&)’
7 | class F1Team {
| ^~~~~~
test.cpp:7:7: note: candidate expects 1 argument, 0 provided
test.cpp:7:7: note: candidate: ‘F1Team::F1Team(F1Team&&)’
test.cpp:7:7: note: candidate expects 1 argument, 0 provided
I don't understand why the constructor to my class is being called here.
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