Working with multiple ifstreams as a vector of ifstreams

Question

I am trying to read multiple files (3 in this example) line by line and using a vector of ifstream shared_ptrs to do this. But I do not know how to dereference this pointer to use getline() or there's some other error in my code.

vector<shared_ptr<ifstream>> files;

for (char i = '1'; i < '4'; i++) {
        ifstream file(i + ".txt");
        files.emplace_back(make_shared<ifstream>(file));
    }

for (char i = '1'; i < '4'; i++) {
        shared_ptr<ifstream> f = files.at(i - '0' - 1); 
        string line;
        getline(??????, line); //What should I do here?

        // do stuff to line

    }

Answer 1

Dereferencing a shared_ptr is very much like dereferencing a raw pointer:

#include <vector>
#include <fstream>
#include <memory>

int main()
{
    std::vector<std::shared_ptr<std::ifstream>> files;

    for (char i = '1'; i < '4'; i++) {
            std::string file = std::string(1, i) + ".txt";
            files.emplace_back(std::make_shared<std::ifstream>(file));
        }

    for (char i = '1'; i < '4'; i++) {
        std::shared_ptr<std::ifstream> f = files.at(i - '0' - 1); 
        std::string line;
        getline(*f, line); //What should I do here? This.

        // do stuff to line

    }
}

I have corrected the code so that it compiles, but have not addressed style issues as they aren't relevant to the question.

Note: it's easier for the community if you can post a complete minimal program rather than a snippet.