How to enter a single value in a vector of pair? - c++

Question

I am trying out a project in C++ and I am trying to enter a value from an integer type vector to a pair type vector.
I have tried emplace_back and push_back but it doesn't work. Most probably due to the pair typed vector.
Note: I am using boost libraries, not sure if that is helpful.
typedef unsigned int objecttype;
typedef string operationtype;
typedef unsigned int checkob;
typedef pair<objecttype, operationtype> objectops;
vector<vector<unsigned int>> parameters;
//lines returning values to “parameters”
vector<checkob> checkParams = parameters.at(0); // works fine
vector<objectops> objectParams = parameters.at(1); // below error
The error message:
error test.cpp:273:30: error: no viable conversion from 'vector<unsigned int, allocator<unsigned int>>' to 'vector<model:: objectops, allocator<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >>>'
stl_vector.h:326:7: note: candidate constructor not viable: no known conversion from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<unsigned int, std::allocator<unsigned int> > > >::value_type' (aka 'std::vector<unsigned int, std::allocator<unsigned int> >') to 'const std::vector<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > &' for 1st argument
stl_vector.h:344:7: note: candidate constructor not viable: no known conversion from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<unsigned int, std::allocator<unsigned int> > > >::value_type' (aka 'std::vector<unsigned int, std::allocator<unsigned int> >') to 'std::vector<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > &&' for 1st argument
stl_vector.h:383:7: note: candidate constructor not viable: no known conversion from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<unsigned int, std::allocator<unsigned int> > > >::value_type' (aka 'std::vector<unsigned int, std::allocator<unsigned int> >') to 'initializer_list<std::vector<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::value_type>' (aka 'initializer_list<std::pair<unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >') for 1st argument

Answer 1

You are trying to assign std::vector<unsigned int> to std::pair<unsigned int, std::string>, which is obviously not possible.
You can either
assign a vector of std::pair<unsigned int, std::string> to
objectParams
or a list initialization using a pair of the element of the vector
of vector of unsigned int egers(i.e. unsigned int) of parameters
and a std::string.
You probably mean this:
vector<objectops> objectParams ={ { parameters.at(0).at(0), "string"} };
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ std::pair<objecttype, operationtype>
// ^^ ^^ for std::vector<objectops>