Printing all subsets

I have tried to incorporate comments from my previous code review into this. So, I am hoping for less mistakes. If you spot any, please let me know mercilessly!

#include 
#include 

void printsub(int* p, int len, std::queue q) {

    if (!len) {
        while(!q.empty()) {
            std::cout  t1(q);
    t1.push(p[0]);
    printsub(&(p[1]), len - 1, t1);

    std::queue t2(q);
    printsub(&(p[1]), len - 1, t2);
}

int main() {
    int arr[] = {1, 2, 3, 4, 5, 6};                                     

    std::queue q;
    printsub(arr, ((sizeof(arr))/(sizeof(arr[0]))), q);
}

You could translate this recursive Python code.

def xcombinations(items, n):
if n==0: yield []
else:
for i in xrange(len(items)):
for cc in xcombinations(items[:i]+items[i+1:],n-1):
yield [items[i]]+cc


in C++ roughly (untested, but you get the idea):

using std::set;

set xcombinations(const set &items, size_t n) {
set result; // collect for 'return' instead of pythons 'yield'
if(n==0) return result;
for(int elem : items) { // ranged-for from C++11
// 'items' without 'elem', python 'items[:i]+items[i+1:]'
set temp(items); // copy
temp.erase(elem); // ...or use 'std::remove_copy_if'
for(auto cc : xcombinations(temp, n-1)) { // ranged-for from C++11
cc.insert(elem);
result.insert(cc); // python yield;
}
}
return result;
}


Note that auto cc creates a copy in the inner loop, where one can add elem before adding it to result.

Instead if the new C++11 ranged-for and auto one can of course just use lengthy iterator-based for-loops.

Using vector instead of set would also work, I guess. There are no set-operations involved here. Actually, now that I think of it, vector would be much better... hmm...

One could save some copying by pulling temp out of the loop, initialize it with a a size of n-1 and use std::remove_copy_if to put the values into it. And if one does that, one can even save the copy of all values by just replacing one in the inner loop, but I can not see how right away.

Ah, well and you need a printing routine, of course.

std::ostream& operator& items) {
    for(int elem: items)
        os >& itemss) {
    for(const auto &cc: itemss)
        os  data = {1, 2, 3, 4, 5, 6}; // C++11 init-list
    std::cout << xcombinations(data, data.size()) << std::endl;
}

StackExchange Code Review Q#12293, answer score: 3