CODEWITHSUNDEEP
c++vector
Will Walters
Will Walters

Reputation: 17

Vector errors in initialization and push_back of pairs

I'm trying to make a vector of pairs, a object in first and a list of object pointers in second. However, I keep getting this error that there is no matching function.

Query blank_query();
std::list<Movie_Data*> blank_list;
std::vector<std::pair<Query,std::list<Movie_Data*>>> vec (Hsize,std::make_pair(blank_query,blank_list));

I'm getting this error

hash_table.cpp:128:47: error: no matching function for call to ‘std::vector<std::pair<Query, std::__cxx11::list<Movie_Data*> > >::vector(int&, std::pair<Query (*)(), std::__cxx11::list<Movie_Data*> >)’
  (Hsize,std::make_pair(blank_query,blank_list));

Another example

hash_tbl.push_back(std::make_pair(blank_query,blank_list));

Error

hash_table.cpp:177:61: error: no matching function for call to ‘std::vector<std::pair<Query, std::__cxx11::list<Movie_Data*> > >::push_back(std::pair<Query (*)(), std::__cxx11::list<Movie_Data*> >)’
    hash_tbl.push_back(std::make_pair(blank_query,blank_list));

Upvotes: 0

Views: 45

Answers (1)

cigien
cigien

Reputation: 60227

You are a victim of a vexing parse. This line

Query blank_query();

actually declares a function named blank_query, that takes no arguments, and returns a Query.

You need to do something like:

Query blank_query{};

to create a Query object.

Upvotes: 1

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