C++ sorting and keeping track of indexes

Question

Using C++, and hopefully the standard library, I want to sort a sequence of samples in ascending order, but I also want to remember the original indexes of the new samples.<

Answer 1

vector >a;

for (i = 0 ;i < n ; i++) {
    // filling the original array
    cin >> k;
    a.push_back (make_pair (k,i)); // k = value, i = original index
}

sort (a.begin(),a.end());

for (i = 0 ; i < n ; i++){
    cout << a[i].first << " " << a[i].second << "\n";
}

Now a contains both both our values and their respective indices in the sorted.

a[i].first = value at i'th.

a[i].second = idx in initial array.