#include <iostream>
#include <string>
#include <chrono>
#include <iomanip> // oss
/*
Function: dateToString
Purpose : Convert a std::chrono::system_clock::time_point
to a string containing ONLY the date (YYYY-MM-DD)
*/
std::string dateToString(const std::chrono::system_clock::time_point& tp) {
// Convert to time_t (calendar time)
std::time_t rawTime = std::chrono::system_clock::to_time_t(tp);
// Convert to tm structure (broken-down time)
std::tm* timeInfo = std::localtime(&rawTime);
// Format the date into a string
std::ostringstream oss;
oss << std::put_time(timeInfo, "%Y-%m-%d"); // Only date
return oss.str();
}
std::chrono::system_clock::time_point makeDate(int y, int m, int d) {
std::tm t = {};
t.tm_year = y - 1900;
t.tm_mon = m - 1;
t.tm_mday = d;
return std::chrono::system_clock::from_time_t(std::mktime(&t));
}
int main()
{
// Get current system time
auto now = std::chrono::system_clock::now();
std::string dateStr = dateToString(now);
std::cout << "Today's date is: " << dateStr << std::endl;
auto myDate = makeDate(2025, 12, 7);
std::string hardcodedStr = dateToString(myDate);
std::cout << "Hard-coded date is: " << hardcodedStr << std::endl;
using namespace std::chrono;
year_month_day ymd{year{2028}, month{6}, day{21}};
sys_days sd = ymd;
std::cout << "C++20 date: " << dateToString(sd) << std::endl;
}
/*
run:
Today's date is: 2026-05-30
Hard-coded date is: 2025-12-07
C++20 date: 2028-06-21
*/
