Recursive generator in C++

Question

I have a vector of size = N where each element i can have values from 0 to possible_values[i]-1. I want to do a function that iterates me through all those values.

I was

Answer 1

Another implementation.

PS: The printing of the values can be customized to look like the output from Python but I didn't think that was necessary to illustrate the algorithm to generate the output data.

#include 
#include 

using namespace std;

void print_values(vector > const& values)
{
   for ( auto v1 : values)
   {
      for ( auto v : v1 )
      {
         cout << v << " ";
      }
      cout << "\n";
   }
}

vector > get_all_values(int size,
                                    vector::const_iterator iter)
{
   vector > ret;
   if ( size == 1 )
   {
      for (int v = 0; v != *iter; ++v )
      {
         std::vector a = {v};
         ret.push_back(a);
      }
      return ret;
   }

   vector > prev = get_all_values(size-1, iter+1);
   for (int v = 0; v != *iter; ++v )
   {
      for ( vector& v1 : prev )
      {
         std::vector a = {v};
         a.insert(a.end(), v1.begin(), v1.end());
         ret.push_back(a);
      }
   }

   return ret;
}

vector > get_all_values(vector const& in)
{
   return get_all_values(in.size(), in.begin());
}

int main()
{
   vector a{2};
   vector b{2,3};
   vector c{2,3,2};

   cout << "----------\n";
   print_values(get_all_values(a));
   cout << "----------\n";
   print_values(get_all_values(b));
   cout << "----------\n";
   print_values(get_all_values(c));
   cout << "----------\n";

   return 0;
}

The output generated from running the program:

----------
0
1
----------
0 0
0 1
0 2
1 0
1 1
1 2
----------
0 0 0
0 0 1
0 1 0 
0 1 1
0 2 0
0 2 1
1 0 0
1 0 1
1 1 0
1 1 1
1 2 0
1 2 1
----------