Getting all possible combinations of an integrer array in C++

I have an array of integers, for example: a[1,2,3]. I would like to get all possible combinations of these numbers where they don't repeat, possibly with recursion.

I saw something like this done with strings here: Get all combinations without duplicates but don't know how to adapt it to integers without using any standard algorithms.

So I would like something like this as an output: {1},{2},{3},{1,2},{2,3},{1,3},{1,2,3}

Thanks in advance!

You can achieve all permutations of a list with comparable elements using std::next_permutation from <algorithms> library.

The cppreference has a nice article about this: https://en.cppreference.com/w/cpp/algorithm/next_permutation

We can use the code example to apply to your question.

#include <algorithm>
#include <string>
#include <iostream>
#include <vector>

void print_vector(const std::vector<int>& array) {
    for (const int item : array)
    {
        std::cout << item << " ";
    }
    std::cout << std::endl;
}
 
int main()
{
    std::vector<int> a({ 5,1,8,7,2 });
    std::sort(a.begin(), a.end());
    do {
        print_vector(a);
    } while(std::next_permutation(a.begin(), a.end()));
}