text: #include <vector>
  #include <set>
  #include "printer.h"
  
  using namespace std;
  
  int main() {
      vector<int> a = {1, 2, 3, 4, 5, 6, 7};
      vector<int>::iterator a_it = a.begin();
      cout << "vector[0]=" << *a_it << endl;
  
      set<int> b = {1, 2, 3, 4, 5, 6, 7};
      set<int>::iterator b_it = b.begin();
      cout << "set[0]=" << *b_it << endl;
  
      return 0;
  }
  