How do I initialize a vector of a pair of strings in a C++ class? I tried several things but none worked out.
vector<pair<string,string>> myVec(); //doesn't work
A vector of pairs is declared with the expression - vector<pair<int, string>> and it can be initialized the same way as the structure. Once we need to push additional std::pair type elements to the vector , the push_back method can be utilized.
Each element of a string array contains a 1-by-n sequence of characters. You can create a string using double quotes. As an alternative, you can convert a character vector to a string using the string function. chr is a 1-by-17 character vector.
CPP. Initializing a Pair: We can also initialize a pair. Another way to initialize a pair is by using the make_pair() function. g2 = make_pair(1, 'a');
There is no need to initialize a vector such a way
vector<pair<string,string>> myVec();
It is a function declaration with name myVec
that does not have parameters and has return type vector<pair<string,string>>
It is enough to write simply
vector<pair<string,string>> myVec;
because in any case you are creating an empty vector.
Or if you want that the vector had some initial values and your compiler supports C++ 2011 then you can also write for example
std::vector<std::pair<std::string, std::string>> myVec =
{
{ "first", "first" }, { "second", "second" }, { "third", "third" }
};
If you use ()
you run into the most vexing parse. You declared a function myVec
that takes no arguments, and returns a vector<pair<string, string>>
Switch to {}
vector<pair<string,string>> myVec{};
Try to use it like this, presently your function myVec
has no parameters and return vector<pair<string,string>>
:
vector<pair<string,string>> myVec{};
or
vector<pair<string,string>> myVec;
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