b83503104@yahoo.com (b83503104) wrote in message
[color=blue]
> In matlab, the sort function returns two things:
>
> [a,b]=sort([5, 8, 7])
>
> a = 5 7 8
> b = 1 3 2
>
> where a is the sorted result, and b is the corresponding index.
> Is there C++ code available to achieve this?
> Better compatible with STL vector.
> Thanks[/color]
There is no such way in C++. But you can build it yourself.
Here is one suggestion: make your original vector { 5, 8, 7 }, make a
vector of pointers { &orig[0], &orig[1], &orig[2] }, sort the vector
of pointers using std::sort of 3 arguments which should yield {
&orig[0], &orig[2], &orig[1] }.
A second suggestion is: make your original vector a vector of
pair<int, index> as { {5,0}, {8,1}, {7,2} }, sort the vector using
std::sort of 3 arguments which should yield { {5,0}, {7,2}, {8,1} }.
The first way would look something like this:
std::vector<int> orig;
orig.push_back(5);
orig.push_back(7);
orig.push_back(8);
std::vector<const int *> pointer;
pointer.reserve(orig.size());
const int *const start = &orig[0];
const int *const end = start + orig.size();
for (int * iter = start; iter != end; ++iter) pointer.push_back(iter);
std::sort(pointer.begin(), pointer.end(), LessDereference());
where
struct LessDereference {
template <class T>
bool operator()(const T * lhs, const T * rhs) const {
return *lhs < *rhs;
}
};
To print the results, choose whatever option you want. There are many
ways, and here is one:
for (int i=0; i<pointer.size(); i++) {
const int * p = pointer[i];
cout << "(" << *p << "," << p-start << " ";
}
