Как работать с <ctime>?

#include <ctime>
using namespace std;
 
 
int _tmain(int argc, _TCHAR* argv[])
{
    
    tm a;
    cout<<"*************************"<<endl;
    cout<<"tm_hour = "<<a.tm_hour<<endl;
    return 0;
}

int a;
cout << a; // выводит мусор

#include <iostream>
#include <ctime>
 
using namespace std;
 
int main ()
{
  time_t rawtime;
  struct tm * timeinfo;
 
  time (&rawtime);
  timeinfo = localtime (&rawtime);
 
  cout << timeinfo->tm_hour;
 
  return 0;
}

nmcf

struct tm * timeinfo;

#include "stdafx.h"
#include <iostream>
#include <ctime>
 
using namespace std;
 
int _tmain(int argc, _TCHAR* argv[])
{
    time_t rawtime;
    time(&rawtime);
    tm * timeinfo = localtime(&rawtime);
    cout<<"tm_sec = "<<timeinfo->tm_sec<<endl;
    cout<<"tm_min = "<<timeinfo->tm_min<<endl;
    cout<<"tm_hour = "<<timeinfo->tm_hour<<endl;
    cout<<"tm_day = "<<timeinfo->tm_hour<<endl;
    cout<<"tm_mon = "<<timeinfo->tm_mon<<endl;
    cout<<"tm_year = "<<timeinfo->tm_year<<endl;
    cout<<"tm_wday = "<<timeinfo->tm_wday<<endl;
    cout<<"tm_yday = "<<timeinfo->tm_yday<<endl;
    cout<<"tm_isdst = "<<timeinfo->tm_isdst<<endl;
    return 0;
}