Определить сколько секунд осталось до времени2

#include <chrono>
#include <ctime>
#include <iomanip>
#include <iostream>
 
struct Tm : std::tm {
  int tm_usecs; // [0, 999999] micros after the sec
 
  Tm(const int year, const int month, const int mday, const int hour,
     const int min, const int sec, const int usecs, const int isDST = -1)
      : tm_usecs{usecs} {
    tm_year = year - 1900; // [0, 60] since 1900
    tm_mon = month - 1;    // [0, 11] since Jan
    tm_mday = mday;        // [1, 31]
    tm_hour = hour;        // [0, 23] since midnight
    tm_min = min;          // [0, 59] after the hour
    tm_sec = sec;          // [0, 60] after the min
                           //         allows for 1 positive leap second
    tm_isdst = isDST;      // [-1...] -1 for unknown, 0 for not DST,
                           //         any positive value if DST.
  }
 
  template <typename Clock_t = std::chrono::high_resolution_clock,
            typename MicroSecond_t = std::chrono::microseconds>
  auto to_time_point() -> typename Clock_t::time_point {
    auto time_c = mktime(this);
    return Clock_t::from_time_t(time_c) + MicroSecond_t{tm_usecs};
  }
};
 
void split(const std::string &s, char delim, std::vector<std::string> &elems) {
    std::stringstream ss;
    ss.str(s);
    std::string item;
    while (std::getline(ss, item, delim)) {
        elems.push_back(item);
    }
}
 
 
std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    split(s, delim, elems);
    return elems;
}
 
void init(string str, int *h, int *m, int *s)
{
  std::vector<std::string> times = split(str, ":");
  for (int i = 0; i < times.length(); i++)
  {
      int value = std::stoi(times[i]);
      switch(i) {
        case 0: *h = value; break;
        case 1: *m = value; break;
        vase 2: *s = value; break;
        default: break;
     }
  }
}
 
int main() {
  using namespace std::chrono;
 
  string time1;
  cin >> time1;
 
  int h1 = 0;
  int m1 = 0;
  int s1 = 0;
  init (time1, &h1, &m1, &s1);
  
 
  string time2;
  cin >> time2;
 
  int h2 = 0;
  int m2 = 0;
  int s2 = 0;
  init (time2, &h2, &m2, &s2);
  
 
  auto tp_nomicro = Tm(2016, 12, 14, h1, m1, s1, 0).to_time_point();
  auto tp_micro = Tm(2016, 12, 14, h2, m2, s2, 0).to_time_point();
  std::cout << duration_cast<microseconds>(tp_micro - tp_nomicro).count()
            << " microseconds apart.\n";
 
  auto time_c = high_resolution_clock::to_time_t(tp_micro);
  std::cout << std::ctime(&time_c) << '\n';
}

#include <chrono>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <vector>
#include <string>
struct Tm : std::tm {
    int tm_usecs; // [0, 999999] micros after the sec
 
    Tm(const int year, const int month, const int mday, const int hour,
       const int min, const int sec, const int usecs, const int isDST = -1)
        : tm_usecs {usecs} {
        tm_year = year - 1900; // [0, 60] since 1900
        tm_mon = month - 1;    // [0, 11] since Jan
        tm_mday = mday;        // [1, 31]
        tm_hour = hour;        // [0, 23] since midnight
        tm_min = min;          // [0, 59] after the hour
        tm_sec = sec;          // [0, 60] after the min
        //         allows for 1 positive leap second
        tm_isdst = isDST;      // [-1...] -1 for unknown, 0 for not DST,
        //         any positive value if DST.
    }
 
    template <typename Clock_t = std::chrono::high_resolution_clock,
             typename MicroSecond_t = std::chrono::microseconds>
    decltype(auto) to_time_point() {
        auto time_c = mktime(this);
        return Clock_t::from_time_t(time_c) + MicroSecond_t {tm_usecs};
    }
};
 
void split(const std::string &s, char delim, std::vector<std::string> &elems) {
    std::stringstream ss;
    ss.str(s);
    std::string item;
    while (std::getline(ss, item, delim)) {
        elems.push_back(item);
    }
}
 
 
std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    split(s, delim, elems);
    return elems;
}
 
void init(std::string str, int *h, int *m, int *s) {
    std::vector<std::string> times = split(str,':');
    for (int i = 0; i < times.size(); i++) {
        int value = std::stoi(times[i]);
        switch(i) {
            case 0:
                *h = value;
                break;
            case 1:
                *m = value;
                break;
            case 2:
                *s = value;
                break;
            default:
                break;
        }
    }
}
 
int main() {
    using namespace std::chrono;
    std::string time1;
    std::cin >> time1;
    int h1 = 0;
    int m1 = 0;
    int s1 = 0;
    init (time1, &h1, &m1, &s1);
    std::string time2;
    std::cin >> time2;
    int h2 = 0;
    int m2 = 0;
    int s2 = 0;
    init (time2, &h2, &m2, &s2);
    auto tp_nomicro = Tm(2016, 12, 14, h1, m1, s1, 0).to_time_point();
    auto tp_micro = Tm(2016, 12, 14, h2, m2, s2, 0).to_time_point();
    std::cout << duration_cast<seconds>(tp_micro - tp_nomicro).count()
              << " seconds apart.\n";
    auto time_c = high_resolution_clock::to_time_t(tp_micro);
    std::cout << std::ctime(&time_c) << '\n';
}