unordered_map<int, int> storeinhashmap(vector<int>v, int n)
{
    vector<int>::iterator it=v.begin();
    unordered_map<int,int>h;
    int temp;
    while(n--)
    {
        temp = *it;
        h.insert(make_pair<int,int>(n,*it));
        it++;
    }
    return h;
}



int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n, x;
        cin>>n;
        vector<int>v;
        readValues(v, n);
        cin>>x;
        unordered_map<int, int>h = storeinhashmap(v, n);
        //char ans = checksumisx(h, n);

    }
    return 0;
}

harshit@harshit-5570:~/Desktop/geeksforgeeks$ g++ -std=c++14 key_pair.cpp
key_pair.cpp: In function ‘std::unordered_map<int, int> storeinhashmap(std::vector<int>, int)’:
key_pair.cpp:26:43: error: no matching function for call to ‘make_pair(int&, int&)’
         h.insert(make_pair<int,int>(n, *it));
                                           ^
In file included from /usr/include/c++/5/bits/stl_algobase.h:64:0,
                 from /usr/include/c++/5/bits/char_traits.h:39,
                 from /usr/include/c++/5/ios:40,
                 from /usr/include/c++/5/ostream:38,
                 from /usr/include/c++/5/iostream:39,
                 from key_pair.cpp:1:
/usr/include/c++/5/bits/stl_pair.h:276:5: note: candidate: template<class _T1, class _T2> constexpr std::pair<typename std::__decay_and_strip<_Tp>::__type, typename std::__decay_and_strip<_T2>::__type> std::make_pair(_T1&&, _T2&&)
     make_pair(_T1&& __x, _T2&& __y)
     ^
/usr/include/c++/5/bits/stl_pair.h:276:5: note:   template argument deduction/substitution failed:
key_pair.cpp:26:43: note:   cannot convert ‘n’ (type ‘int’) to type ‘int&&’
         h.insert(make_pair<int,int>(n, *it));