Generating the subsets of a set.

subsets.cpp

#include <iostream>
#include <fstream>
#include <vector>
#define FIN "submultimi.in"
#define FOUT "submultimi.out"

using namespace std;

int main() {

    int n;

    ifstream fin(FIN);

    ofstream fout(FOUT);

    fin>>n;

    vector<int> stack;

    stack.push_back( 1 );

    while(!stack.empty()) {

          for(vector<int>::size_type i = 0; i < stack.size(); ++i) fout<<stack[i]<<" ";

          fout<<endl;

          if(stack.back() < n) {

             stack.push_back(stack.back() + 1);

          } else {

             stack.pop_back();

             if(!stack.empty()) stack.back()++;
          }
    }  

    return(0);
};