Is there any standard function that sorts vectors? It seems that qsort()
does only sort arrays. Is that right?

Florian

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Florian Eisele wrote:

> Is there any standard function that sorts vectors?

std::sort is a template function which will probably do what you
want.  std::stable_sort is a related function which will preserve
the order of "equal" elements, but might be slower.

std::sort is typesafe and given a good compiler can be faster
that the qsort function which was inherited from C.  It certainly
makes code less ugly.

If you're writing C++ you ought to have a good reference book;
looking up sort in the index will probably take you to std::sort
at least to give you more details.

 > It seems that qsort() does only sort arrays.  Is that right?


Yes, qsort is only designed to sort arrays.

-- James Dennett <jdennett@acm.org>

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Try std::sort. It sorts any container which has random access iterators.
Qsort ? Bah ! This is a C++ forum. Real men and women not only eat quiche but
they also use C++ standard algorithms <g>. BTW my main compiler's version
std::sort uses a quicksort algorithm.

Florian Eisele wrote:

> Is there any standard function that sorts vectors? It seems that qsort()
> does only sort arrays. Is that right?

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Florian Eisele wrote:
>
> Is there any standard function that sorts vectors? It seems that qsort()
> does only sort arrays. Is that right?

std::sort(v.begin(), v.end()) will do the job quite nicely.

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"Florian Eisele" <florian.eisele@gmx.net>:
> Is there any standard function that sorts vectors? It seems that qsort()
> does only sort arrays. Is that right?

How about std::sort.

sm



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In article <93q9cj$imv$1@news.netcologne.de>, Florian Eisele wrote:
> Is there any standard function that sorts vectors? It seems that qsort()
> does only sort arrays. Is that right?

#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <vector>

using namespace std;

int
main(int argc, char** argv)
{
  vector<int> vec;
  vector<int>::const_iterator iter;

  // Insert some random numbers.
  srand(time(0));
  for (int i = 0; i < 6; i++)
    vec.push_back(rand() % 20);

  // Print the vector contents.
  for (iter = vec.begin(); iter != vec.end(); ++iter)
    cout << *iter << ' ';
  cout << endl;

  // Sort the vector.
  sort(vec.begin(), vec.end());

  // Print the vector contents again.
  for (iter = vec.begin(); iter != vec.end(); ++iter)
    cout << *iter << ' ';
  cout << endl;

  return 0;
}


A sample output for the above program is:

4 1 14 19 12 5
1 4 5 12 14 19

Note that sorting the vector is as simple as calling sort() with the start
and end of the range you want sorted.

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>>>>> "Florian" == Florian Eisele <florian.eisele@gmx.net> writes:

    Florian> Is there any standard function that sorts vectors? It
    Florian> seems that qsort() does only sort arrays. Is that right?

There is a set of sorting operations available under the standard
algorithms library. See section 25.3 in the C++ standard or look up
"algorithms" in a C++ book.

--
Pagey

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"Florian Eisele" <florian.eisele@gmx.net> wrote...
> Is there any standard function that sorts vectors? It seems that qsort()
> does only sort arrays. Is that right?

#include <vector>
#include <algorithm>

using namespace std;

void somefunc()
{
    // create a vector
    vector<int> v;

    // do something to fill vector

    // sort the vector using this template from <algorithms>
    sort(v.begin(),v.end());
}

I'm not at a compiler right now, but I believe the above is essentially
correct... the <algorithms> header file includes a number of useful tools.

I hope that helps!

--
Scott Robert Ladd
http://www.coyotegulch.com


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In article <93q9cj$imv$1@news.netcologne.de>, Florian Eisele
<florian.eisele@gmx.net> writes
>Is there any standard function that sorts vectors? It seems that qsort()
>does only sort arrays. Is that right?

To even ask this question means that you have completely missed what the
STL is about. There are a whole range of template functions to sort
vectors that include sort, partial_sort, and stable_sort. Assuming the
objects you wish to sort have an operator< provided the following line
sorts a vector v of objects in ascending order:

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

That could hardly be simpler. Actually the same function will sort an
array a of n objects:

sort(a, a+n);


There are also versions that allow you to provide comparison functions.
The whole system of containers and algorithms in the C++ Standard
Library is orders of magnitude more sophisticated than the C facilities
and they can almost all be applied to raw C arrays as well as to C++
containers.

However you really should be asking questions like this on
comp.lang.c++.moderated

Francis Glassborow      Association of C & C++ Users
64 Southfield Rd
Oxford OX4 1PA          +44(0)1865 246490
All opinions are mine and do not represent those of any organisation

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