Example of the use of std vector, set, stringstream and for_each

vector_set_example.cpp

#include <iostream>

#include <algorithm>
#include <set>
#include <vector>
#include <string>
#include <sstream>


std::string set_to_string(std::set<int> set) {
    std::stringstream out;
    
    out << '{';
    
    if (!set.empty())
    {
        for_each(
            set.begin(), 
            --set.end(), 
            [&out](const int &value) 
            {
                out << value << ',';
            }
        );
        
        out << *(--set.end());
    }
    
    out << '}';
    out.flush();
    
    return out.str();
}

int main()
{
    std::vector<std::set<int>> vector;
    
    std::set<int> aux = { 0 };
    vector.push_back(aux);

    aux = {1,2,4,8,16};
    vector.push_back(aux);

    aux = {};
    vector.push_back(aux);

    for_each(
        vector.begin(), 
        vector.end(),
        [](const auto value)
        {
            std::cout << set_to_string(value) << "\n";
        }
    );

}