#include <vector>
#include <iostream>

//   shorthand for an iterator that allows us to work with elements of
//     a vector<int> without changing that vector

typedef std::vector<int>::const_iterator IVEC;


int main()
{
     std::vector<int> ivec(0);    //  initial size of vector is zero

     ivec.push_back(5);
     ivec.push_back(6);

     // output the elements
     for (int i = 0, size = ivec.size(); i < size; ++i)
         std::cout << ' ' << ivec[i];
     std::cout << '\n';

     ivec.resize(1);    // resize vector to 1 elements (incidentally discard last one)

     ivec.push_back(5);   // vector size will now be 2
     ivec.push_back(6);   // vector size will now be 3

     // another way to output it

     for (IVEC i = ivec.begin(), end = ivec.end(); i != end; ++i)
         std::cout << ' ' << *i;
      std::cout << '\n';

      return 0;
}