Modifying a tuple in a vector of tuples c++

Question

I have a vector of tuples vector<tuple<int,int>> vector; and I want to modify one of the tuples it contains.

for (std::tuple<int, int> tup : std::vector)
{
    if (get<0>(tup) == k)
    {
        /* change get<1>(tup) to a new value
         * and have that change shown in the vector
         */
    }
}

I am unsure how to change the value of the tuple and have the change be reflected in the vector. I have tried using

get<1>(tup) = v;

but that doesn't change the value of the tuple that is in the vector. How can I do this? Thanks.

Answer 1

Capture the tuple by reference:

for (tuple<int, int> &tup : vector){
//                   ^here
    if (get<0>(tup) == k){
        get<1>(tup) = v;
    }
}

Answer 2

You just need to use a reference instead of a value in your for-loop:

for (tuple<int, int>& tup : vector){