Comparison of C++ string writing

oldvsnew.cpp

#include <vector>
#include <string>
#include <map>
#include <iostream>

using namespace std;

/*
d = {"primes" : [2, 3, 5, 7],
     "fib": [1, 1, 2, 3]}
print d
 */


void print1(){
  map<string, vector<int>> msv;
  vector<int> v;
  v.push_back(2);
  v.push_back(3);
  v.push_back(5);
  v.push_back(7);
  msv["primes"] = v;
  v.clear();
  v.push_back(1);
  v.push_back(1);
  v.push_back(2);
  v.push_back(3);
  msv["fib"] = v;
  map<string, vector<int>>::iterator endi = msv.end();
  for(map<string, vector<int>>::iterator i = msv.begin(); i != endi; i++){
    cout << i->first << ": ";
    vector<int>::iterator endvi = i->second.end();
    bool first = true;
    for(vector<int>::iterator vi = i->second.begin(); vi != endvi; vi++){
      if(!first){
        cout << ", ";
      } else {
        first = false;
      }
      cout << *vi;
    }
    cout << endl;
  }
}

void print2(){
  map<string, vector<int>> msv = {{"primes", {2, 3, 5, 7}},
                                  {"fib", {1, 1, 2, 3}}};

  for(auto i: msv){
    cout << i.first << ": ";
    bool first = true;
    for(auto vi: i.second){
      if(!first){
        cout << ", ";
      } else {
        first = false;
      }
      cout << vi;
    }
    cout << endl;
  }
}

template<List>
string show_list(const List &l){
  return join(l | transform([](x){return (format("%1%") % x).str();}), ", ");
}

void print3(){
  map<string, vector<int>> msv = {{"primes", {2, 3, 5, 7}},
                                  {"fib", {1, 1, 2, 3}}};

  join(msv | transform([](x){return (format("%1%: [%2%]") % x.first % show_list(x.second)).str();}), "\n")
}

int main(void){
  print1();
  print2();
}