//Purpose:
//  Generate characteristic functions for subsets of a set.
//
#include <iostream>
#include <iomanip>
#include <vector>
typedef std::vector<bool> char_fun_t;
typedef std::vector<char_fun_t> char_funs_t;

  std::ostream&
operator<<
  ( std::ostream& sout
  , char_fun_t const& l
  )
{
    for (char_fun_t::const_iterator ii = l.begin(); ii!=l.end(); ++ii) {
      sout<<std::setw(2)<< *ii ;
    }
    return sout;
}  
 
  std::ostream&
operator<<
  ( std::ostream& sout
  , char_funs_t const& mm
  )
{
    for (char_funs_t::const_iterator i = mm.begin(); i!=mm.end(); ++i) {
      char_fun_t const& l = *i;
      std::cout<<l;
      std::cout<<std::endl;
    }
    return sout;
}

void gen_char_fun(char_funs_t& char_funs_v, char_fun_t& char_fun_v, int index)
{
    if(index<0)
    {
        char_funs_v.push_back(char_fun_v);
    }
    else
    {
        for(int yes_no=0; yes_no<2; ++yes_no)
        {
            char_fun_v[index]=yes_no;
            gen_char_fun(char_funs_v, char_fun_v, index-1);
        }
    }
}
void gen_char_funs(char_funs_t& char_funs_v, int size)
{
    char_fun_t char_fun_v(size);
    gen_char_fun(char_funs_v, char_fun_v, size-1);
}
 
int main(void)
{
    char_funs_t char_funs_v;
    gen_char_funs(char_funs_v, 5);
 
    std::cout<< "size="<< char_funs_v.size() <<std::endl;
    std::cout<<char_funs_v;
    return 0;
}