Adding to a vector of pair

Question

I have a vector of pair like such:

vector> revenue;

I want to add a string and a doub

Answer 1

Using emplace_back function is way better than any other method since it creates an object in-place of type T where vector<T>, whereas push_back expects an actual value from you.

vector<pair<string,double>> revenue;

// make_pair function constructs a pair objects which is expected by push_back
revenue.push_back(make_pair("cash", 12.32));

// emplace_back passes the arguments to the constructor
// function and gets the constructed object to the referenced space
revenue.emplace_back("cash", 12.32);

Answer 2

IMHO, a very nice solution is to use c++11 emplace_back function:

revenue.emplace_back("string", map[i].second);

It just creates a new element in place.

Answer 3

Try using another temporary pair:

pair<string,double> temp;
vector<pair<string,double>> revenue;

// Inside the loop
temp.first = "string";
temp.second = map[i].second;
revenue.push_back(temp);

Answer 4

Use std::make_pair:

revenue.push_back(std::make_pair("string",map[i].second));

Answer 5

You can use std::make_pair

revenue.push_back(std::make_pair("string",map[i].second));

Answer 6

revenue.push_back(pair<string,double> ("String",map[i].second));

this will work.