vektor vektor

#include <iostream>
#include<stdexcept>
#include<vector>

std::vector<double> funkcija(std::vector<double>a, std::vector<int> b)
{

    std::vector<double> c;
    for (int i(0); i<b.size(); i++)
    {
        c.push_back(a[b[i]]);
        if(a.size() < b[i]) throw std::range_error("Ne moze...");
    }
    return c;
}
int main()
{
    std::vector<int> b;
    std::vector<double>a;
    std::vector<double> c;
    int m,n;
    std::cout<<"Unesi dimenzije vektora a i b:\n";
    std::cin>>n>>m;
    std::cout<<"Unesi elemente vektora a:\n";
    for (int i(0); i<n; i++)
    {
        int pom1;
        std::cin>>pom1;
        a.push_back(pom1);
    }
    std::cout<<"\nUnesi elemente vektora b:\n";
    for (int i(0); i<m; i++)
    {
        int pom2;
        std::cin>>pom2;
        b.push_back(pom2);
    }
    try
    {
        c = funkcija(a,b);
        for(int i(0); i<c.size(); i++)
        {
            std::cout<<c[i]<<" ";
        }
    }
    catch(std::range_error e)
    {
        std::cout<<e.what();
    }
    return 0;
}