Permutation algorithm C++

Question

I try to translate an algorithm that generates all permutations of k out of n in C++ :

public void calculerEquipeTOT(ArrayList<Nageur> L, ArrayList<Nageur> F, int k) {

    if (k == 0) {
        if (calculerPointsTOT(L) > this.pointsMeilleureEquipe){
            this.meilleureEquipe = L;
            this.pointsMeilleureEquipe = calculerPointsTOT(meilleureEquipe);
        }
    } else {
        for (Nageur x : F) {
            ArrayList<Nageur> G = new ArrayList<Nageur>(F);
            G.remove(G.indexOf(x));
            ArrayList<Nageur> L2 = new ArrayList<Nageur>(L);
            L2.add(x);
            calculerEquipeTOT(L2, G, k - 1);
        }
    }
}

My problem is that the Lists could be Objects list and I don't know how to remove the x of the L2 list... I am not a C++ specialist, I managed it in Java but I have to do it in C++.

Answer 1

I have transliterated your function and I have gotten the following

#include <iostream>
#include <list>
#include <iterator>

void arrangements( std::list<char> l, std::list<char> f, size_t k ) 
{
    if ( k == 0 ) 
    {
        for ( char c : l ) std::cout << c << ' ';
        std::cout << std::endl;
    } 
    else 
    {
        for ( auto it = f.begin(); it != f.end(); ++it )
        {
            std::list<char> g( f.begin(), it );
            g.insert( g.end(), std::next( it ), f.end() );

            std::list<char> l2( l );
            l2.push_back( *it );

            arrangements( l2, g , k-1 );
        }
    }
}

int main()
{
    std::list<char> f = { 'A', 'B', 'C', 'D' };

    arrangements( std::list<char>(), f, 2 );
}

The program output is

A B 
A C 
A D 
B A 
B C 
B D 
C A 
C B 
C D 
D A 
D B 
D C 

I do not know whether it is what you want to get.

If to call the function with k equal to 3 then the program output will be

A B C 
A B D 
A C B 
A C D 
A D B 
A D C 
B A C 
B A D 
B C A 
B C D 
B D A 
B D C 
C A B 
C A D 
C B A 
C B D 
C D A 
C D B 
D A B 
D A C 
D B A 
D B C 
D C A 
D C B