Get and print current date and time in C++

date_time.cpp

// Example output from this code:
// Tue Jan 13 12:09:53 2015 (from ctime)
// 20150113_12_09_53 (from strftime)
// 20150113_12_09_53 (from put_time)

#include <ctime>
#include <chrono>
#include <iomanip>

// Get current time
std::chrono::time_point<std::chrono::system_clock> time_now = std::chrono::system_clock::now();

// Print time using ctime
std::time_t time_now_t = std::chrono::system_clock::to_time_t(time_now);
std::cout << std::ctime(&time_now_t) << std::endl;

// Format time and print using strftime
std::tm now_tm = *std::localtime(&time_now_t);
char buf[512];
std::strftime(buf, 512, "%Y%m%d_%H_%M_%S", &now_tm);
std::cout << buf << std::endl;

// Format time and print using put_time
std::stringstream ss;
ss << std::put_time(&now_tm, "%Y%m%d_%H_%M_%S");
std::cout << ss.str() << std::endl;

You missed #include <sstream>

visual studio 2019 aint allowing to build code with localtime without disabling CRT warnings