Pair (C++) need to include #include <utility> pair<string,double> product1; // default constructor pair<string,double> product2 ("tomatoes",2.30);// value init pair<string,double> product3 (product2); // copy constructor Working with a queue queue<pair<int, int>> q; q.push({1,2}); auto [x,y] = q.front();q.pop();