Current date and time as string

Question

I wrote a function to get a current date and time in format: DD-MM-YYYY HH:MM:SS. It works but let's say, its pretty ugly. How can I do exactly the same thing but simpler?

string currentDateToString() {     time_t now = time(0);     tm *ltm = localtime(&now);      string dateString = "", tmp = "";     tmp = numToString(ltm->tm_mday);     if (tmp.length() == 1)         tmp.insert(0, "0");     dateString += tmp;     dateString += "-";     tmp = numToString(1 + ltm->tm_mon);     if (tmp.length() == 1)         tmp.insert(0, "0");     dateString += tmp;     dateString += "-";     tmp = numToString(1900 + ltm->tm_year);     dateString += tmp;     dateString += " ";     tmp = numToString(ltm->tm_hour);     if (tmp.length() == 1)         tmp.insert(0, "0");     dateString += tmp;     dateString += ":";     tmp = numToString(1 + ltm->tm_min);     if (tmp.length() == 1)         tmp.insert(0, "0");     dateString += tmp;     dateString += ":";     tmp = numToString(1 + ltm->tm_sec);     if (tmp.length() == 1)         tmp.insert(0, "0");     dateString += tmp;      return dateString; } 

Answer 1

Non C++11 solution: With the <ctime> header, you could use strftime. Make sure your buffer is large enough, you wouldn't want to overrun it and wreak havoc later.

#include <iostream> #include <ctime>  int main () {   time_t rawtime;   struct tm * timeinfo;   char buffer[80];    time (&rawtime);   timeinfo = localtime(&rawtime);    strftime(buffer,sizeof(buffer),"%d-%m-%Y %H:%M:%S",timeinfo);   std::string str(buffer);    std::cout << str;    return 0; } 

Answer 2

Since C++11 you could use std::put_time from iomanip header:

#include <iostream> #include <iomanip> #include <ctime>  int main() {     auto t = std::time(nullptr);     auto tm = *std::localtime(&t);     std::cout << std::put_time(&tm, "%d-%m-%Y %H-%M-%S") << std::endl; } 

std::put_time is a stream manipulator, therefore it could be used together with std::ostringstream in order to convert the date to a string:

#include <iostream> #include <iomanip> #include <ctime> #include <sstream>  int main() {     auto t = std::time(nullptr);     auto tm = *std::localtime(&t);      std::ostringstream oss;     oss << std::put_time(&tm, "%d-%m-%Y %H-%M-%S");     auto str = oss.str();      std::cout << str << std::endl; }